Paul Christie: ROBBERY.

ARSON.

MURDER.

THE CLASSIC WHODUNITS.

BUT EVERY CRIME LEAVES CLUES.

SOMETHING HERE CAN IDENTIFY THE GUILTY PARTY.

MEET A SPECIAL BREED OF DETECTIVE, FORENSIC SCIENTISTS WHO LOOK TO ANIMALS AND PLANTS AS THE ULTIMATE WITNESSES.

Woman: WE TRY TO USE THIS SPECIES OF MAGGOT TO SOLVE A MURDER.

Man: THERE ARE 300,000 DIFFERENT KINDS OF PLANTS IN THE WORLD.

JUST LIKE ANIMALS, THEY CAN HAVE IMPORTANT FORENSIC USES.

Christie: AND THEIR TESTIMONY IS SO ACCURATE, WHAT THEY SAY CAN AND WILL BE HELD AGAINST YOU.

MEET THE FLIES ON THE FRONT LINES IN THE WAR ON TERROR.

STRANGE UNDERWATER CREATURES THAT CAN TRACK A KILLER.

AND INSECTS THAT CAN DETECT BULLETS.

GO BEHIND THE YELLOW TAPE AND INTO THE SCENE OF THE CRIME.

THIS PROGRAM WAS MADE POSSIBLE BY THE CORPORATION FOR PUBLIC BROADCASTING AND BY CONTRIBUTIONS TO YOUR PBS STATION FROM VIEWERS LIKE YOU.

Christie: A PIG, DECEASED, IS A PERFECT SUBSTITUTE FOR A HUMAN CORPSE.

IT DECOMPOSES IN PRECISELY THE SAME WAY.

THE PIG EVEN WEARS CLOTHES, AS MOST CORPSES DO.

CRIME SCENE SCIENTISTS ARE SETTING THE STAGE OF A MURDER IN THE WOODS.

CAMERAS AND MOTION DETECTORS ARE HIGH-TECH WITNESSES.

SOME ARE DESIGNED TO FILM AT NIGHT.

OTHER ARE SET OFF BY EVEN THE SLIGHTEST MOTION.

ANY VISITORS TO THE BODY WILL BE CAUGHT ON FILM.

THIS SIMULATION IS OF A DOUBLE MURDER, AND THE SCIENTIST DISPOSES OF THE SECOND BODY IN WATER.

ANY INCRIMINATING CLUES SHOULD BE WASHED AWAY.

THE MURDER WEAPON, HE'LL BURN IT TO DESTROY THE EVIDENCE.

THE SCIENTIST HAS DONE EVERYTHING HE CAN TO COVER HIS TRACKS.

THE RE-CREATION OF THE CRIME IS OFF AND RUNNING.

AN INFRARED CAMERA CAPTURES HIS MOVEMENTS AS HIS BODY HEAT GIVES HIM AWAY.

BUT WHEN A CASE REQUIRES HOT PURSUIT, THE POLICE STILL USE ANIMAL DETECTIVES.

THE GERMAN SHEPHERD DOESN'T NEED THE SCENT OF THE SCIENTIST.

HE'S FOLLOWING THE TRAIL OF TRAMPLED VEGETATION.

AND DON'T BELIEVE THE PRISON ESCAPE MOVIES.

RUNNING THROUGH WATER WON'T HELP.

HE'S DISTURBED THE SEDIMENT ON THE BOTTOM, RELEASING BUBBLES OF GAS, WHICH THE DOG DETECTS AT THE SURFACE.

THE SUSPECT'S BEEN APPREHENDED, BUT THE POLICE DON'T KNOW WHEN HE COMMITTED HIS CRIME OR HOW OR WHERE.

UNTIL THEY CAN PROVE THEIR CASE, THEY'LL HAVE TO LET HIM GO.

DEEP IN THE WOODS, THE BODY OF THE DEAD PIG IS BEGINNING TO ATTRACT LOCAL WILDLIFE.

VISITORS TO THE BODY START THE CLOCK ON A NEW CHAIN OF EVIDENCE.

A CROW CAN USE A BODY TO FEED ITS CHICKS.

OTHER ANIMALS GO ONE STEP FURTHER.

THE LIFE CYCLE OF FLIES PLAYS OUT ON AN EXACT TIMELINE AND CAN BE USED TO SHOW PRECISELY WHEN A MURDER WAS COMMITTED.

FLIES MAKE EXCELLENT WITNESSES.

FORENSIC SCIENTISTS DEMONSTRATE WHY.

IN PERTH, AUSTRALIA, LOCAL RESIDENTS GATHER TO WATCH THESE STRANGE GOINGS-ON.

HERE, THE PIG EXPERIMENT IS BEING REPEATED ON A GRAND SCALE.

SCIENTIST IAN DADOUR AND HIS TEAM RECORD PRECISELY HOW LONG FLY MAGGOTS TAKE TO HATCH AND COLONIZE A CORPSE.

Dadour: WHAT WE'RE INTERESTED IN AS THE PIG DECOMPOSES IS HOW FLIES DEVELOP ON THEM.

WE LOOK AT THE NATURAL HISTORY OF THE FLY AND HOW THEY ACTUALLY DEVELOP ON THE CORPSE.

AND THEN WE CAN DETERMINE FROM THAT HOW LONG A BODY'S BEEN DEAD FOR.

Christie: A FLY CAN SMELL DEAD FLESH FROM OVER A MILE AWAY.

AND ONCE SHE'S FOUND IT, SHE CHURNS OUT 50 OR SO EGGS.

WITHIN 24 HOURS, THE EGGS HATCH AS MAGGOTS, TINY EATING MACHINES THAT GORGE DAY AND NIGHT.

WHEN FULLY GROWN, THE LEAVE TO TRANSFORM INTO PUPAE, JUST LIKE THE CHRYSALIS OF A BUTTERFLY.

FROM THESE, ADULT FLIES WILL EMERGE.

IF YOU KNOW HOW LONG THIS CYCLE TAKES UNDER DIFFERENT CONDITIONS IN A PARTICULAR FLY SPECIES, YOU CAN TELL HOW LONG THE BODY THEY'RE LIVING ON HAS BEEN THERE.

THESE SHOTS, SPED UP 25,000 TIMES, SHOW WHAT VORACIOUS MAGGOTS CAN DO IN JUST TWO WEEKS.

THE TEMPERATURE INSIDE THE MAGGOT MASS CAN BE 20° HIGHER THAN OUTSIDE.

THIS AND OTHER FACTORS LIKE HUMIDITY ALSO AFFECT THE SPEED OF DECOMPOSITION.

TO CORROBORATE THESE FIELD EXPERIMENTS, OTHER TESTS ARE DONE IN A HIGH-TECH LAB.

BUT THE FLY CLOCK CAN ALSO BE AFFECTED BY THE WAY SOMEONE DIES.

AND THERE ARE MANY STRANGE AND UNUSUAL WAYS TO MEET YOUR MAKER.

Dadour: THERE'S A THOUSAND DIFFERENT WAYS YOU CAN KILL A PERSON, AND WE'RE TRYING TO SIMULATE WHAT PEOPLE DO TO OTHER PEOPLE.

SOME PEOPLE MIGHT DISGUISE A BODY, AND THEY'LL PUT VEGETATION OVER THE TOP.

AND IF THEY DO THAT, THEN WHAT HAPPENS IS, IS THAT THE FLIES ARE DELAYED.

AND WE KNOW THAT NOW IT'S A 24-HOUR TIME LAG BEFORE THE FLIES COME ONTO THE BODY.

Christie: SUICIDES ARE A DIFFERENT MATTER.

IAN'S TEAM HAVE DISCOVERED THAT MAGGOTS FALL OFF A HANGING PIG, MAKING DECOMPOSITION SLOWER.

WHAT HAPPENS IF SOMEBODY TAKES THEIR OWN LIFE IN A FUME-FILLED CAR?

IAN PREPARES AN INGENIOUS EXPERIMENT TO FIND OUT.

HE SETS UP CAMERAS TO RECORD A SIMULATED SUICIDE FROM CAR EXHAUST FUMES.

OF COURSE, THE PIG'S ALREADY BEEN HUMANELY KILLED.

BUT IAN IS TRYING TO FIND OUT HOW CARBON MONOXIDE AFFECTS FLIES AND THEIR PROGENY.

[ STARTS ENGINE ] EXHAUST IS PUMPED INTO THE CAR FOR EIGHT HOURS STRAIGHT.

BUT THE CARBON MONOXIDE DOESN'T DETER THE FLIES.

THEY STILL FIND A WAY IN TO START THE FEAST.

NOW, THE CAR ACTS LIKE A GREENHOUSE.

THE HOT AND HUMID CONDITIONS MEAN FEEDING IS RAPID FIRE AND THE MEAL IS FINISHED FASTER THAN NORMAL, VITAL INFORMATION FOR INVESTIGATORS COMING ACROSS THIS KIND OF DEATH.

IAN'S FINDINGS ARE PASSED ON TO THE LOCAL POLICE.

Dadour: SO IN THESE BURIALS, WHAT YOU GENERALLY FIND IS, YOU FIND THAT, UH, FLY LARVAE AND OTHER INSECT MATERIAL, UM, ABOVE 40 CENTIMETERS.

IF THE PERSON'S BEEN BURIED ABOUT 40 CENTIMETERS OR LESS FROM THE SURFACE, YOU FIND THE INSECT MATERIAL.

IF IT'S BELOW, YOU DON'T FIND INSECT MATERIAL, AT LEAST THAT'S IN THE AUSTRALIAN ENVIRONMENT.

Christie: THIS IS VICTORIA UNIVERSITY, MELBOURNE.

IT'S ALSO MAGGOT HEAVEN.

SCIENTIST MELANIE ARCHER NURTURES HER MAGGOTS LOVINGLY.

THEY LIVE IN LUXURY AT IDEAL TEMPERATURES IN A SPECIALLY PREPARED MEAT BROTH.

MELANIE IS STUDYING THE SOCIAL LIFE OF THE MAGGOTS TO SEE IF THAT, TOO, CAN AFFECT THE SPEED WITH WHICH THEY DESTROY A BODY.

HERE WE HAVE TWO SPECIES OF MAGGOT.

IF YOU'VE GOT TWO SPECIES GROWING TOGETHER AND THE EFFECT THAT THEY HAVE ON EACH OTHER IS TO EITHER SPEED UP OR SLOW DOWN THE GROWTH OF THE OTHER SPECIES.

AND THAT COULD DRASTICALLY AFFECT OUR ESTIMATES OF THE MINIMUM TIME SINCE DEATH.

THIS MAGGOT'S A PREDATOR.

AND WHAT WE FOUND THROUGH OUR EXPERIMENTS AND TESTS IS THAT THEY CAN ACTUALLY DRIVE THE PREY SPECIES OFF A BODY BEFORE THEY'RE READY TO LEAVE.

Christie: THESE HAIRY MAGGOTS USE SHARP MOUTH PARTS TO PIERCE THEIR SMOOTH-SKINNED COUSINS AND SUCK THEM DRY.

Archer: AND THIS IS THE TYPE OF THING THAT'S VERY IMPORTANT TO KNOW IF YOU'RE TRYING TO USE THIS SPECIES OF MAGGOT TO SOLVE A MURDER.

Christie: BUT SCIENTISTS LIKE MELANIE USING KNOWLEDGE GLEANED FROM DECADES OF WORK WITH FLIES CAN SOLVE LESS SERIOUS CRIMES, TOO.

THIS SPECIAL DELIVERY HORRIFIED THE HOMEOWNER WHEN HE RETURNED AFTER TWO DAYS AWAY.

HIS RECENTLY FIRED HOUSEKEEPER ADMITTED DELIVERING THE FISH BUT SAID THEY WERE A GIFT, FRESH WHEN SHE LEFT THEM, AND THE MAGGOTS MUST HAVE GROWN FROM EGGS.

BUT THE LARVAE WERE AT LEAST SEVEN DAYS OLD.

AND ONLY MAGGOTS SOLD AS BAIT ARE DYED THIS LURID PINK, PROOF THAT HIS PEEVED HOUSEKEEPER HAD LEFT THE MAGGOT-INFESTED FISH TO PUNISH HIM FOR FIRING HER.

THIS IS LEE GOFF.

HE IS A CRIME FIGHTER IN HAWAII WHO USES THE LIFE CYCLE OF FLIES TO BRING KILLERS TO JUSTICE.

ONE OF HIS MOST DIFFICULT CASES INVOLVED A BODY IN A BLANKET.

Goff: I WAS CONTACTED BY THE POLICE AND THE MEDICAL EXAMINER AND ASKED TO GO OUT TO THE NORTH SHORE AND TAKE A LOOK AT THE BODY.

IT WAS WRAPPED IN TWO LAYERS OF BLANKETS.

ONE OF THE MAIN THINGS WE SAW WERE MAGGOTS OF THE HAIRY BLOWFLY, ALSO PUPARIA.

NO FLIES HAD EMERGED FROM THESE YET, SO WE WERE STILL IN FIRST INITIAL WAVE OF INVASION.

I TOOK THESE BACK TO MY LABORATORY, PUT THEM IN THE REARING CHAMBER.

AND WHEN THE ADULTS EMERGED, I FOUND, USING WEATHER DATA, I WAS ABLE TO ACCOUNT FOR 10.5 DAYS OF INSECT ACTIVITY ON THIS PARTICULAR BODY.

Christie: SO THE FLIES SEEMED TO INDICATED THAT THE MURDER HAD BEEN COMMITTED 10.5 DAYS BEFORE THE BODY WAS FOUND.

TO FIND OUT IF THAT WAS TRUE, LEE HAD TO TAKE HIS WORK HOME WITH HIM.

HE WRAPPED A DEAD PIG IN BLANKETS, JUST LIKE THE REAL VICTIM.

TIMING WAS CRUCIAL IN THIS CASE BECAUSE WITNESSES HAD HEARD THE MAIN SUSPECT, THE ESTRANGED HUSBAND, HAVING A VIOLENT FIGHT WITH HIS WIFE JUST 13 DAYS BEFORE.

IT TOOK THE FLIES 2.5 DAYS TO WORK THEIR WAY THROUGH THE BLANKETS TO THE BODY BENEATH.

Goff: SO THE 2.5 DAYS PLUS 10.5 DAYS GAVE US 13 DAYS, THE EXACT TIME THAT THE WOMAN HAD LAST BEEN SEEN ALIVE AND SOUNDS OF A COMMOTION WERE HEARD COMING FROM HER APARTMENT BY NEIGHBORS.

THIS PUT HER IN THE COMPANY OF THE CHIEF SUSPECT, WHO WAS HER ESTRANGED HUSBAND.

HE WAS SUBSEQUENTLY CONVICTED OF MURDER.

Christie: IN ANOTHER EXTRAORDINARY CASE, LEE HAD TO PINPOINT A TIME OF DEATH FROM 2,500 MILES AWAY USING ONLY WEATHER DATA, PHOTOS, AND INSECT SPECIMENS.

THE VICTIM HAD BEEN FOUND ON A CALIFORNIA NAVAL BASE.

Goff: IN FACT, THE PHOTOGRAPHS WERE SO GOOD THAT I COULD ACTUALLY IDENTIFY ONE OF THE SPECIES OF ROVE BEETLE FROM THE PHOTOGRAPHS.

AND THEY ALSO SENT ME A SERIES OF LIVE PUPARIA, WHICH I WAS ABLE TO PUT IN THE REARING CHAMBER AND THEN REAR THESE THROUGH THE ADULT STAGE.

Christie: THE CASE HINGED ON THE IDENTITY OF THE FLIES.

IT WORKED OUT THAT THE DEATH HAD MOST PROBABLY OCCURRED BETWEEN 10:00 P.M. AND MIDNIGHT, 3.5 DAYS BEFORE DISCOVERY OF THE BODY.

THIS WOULD HAVE PUT THE ONSET OF INSECT ACTIVITY ACTUALLY DURING THE HOURS OF DARKNESS, WHICH IS UNUSUAL FOR A FLY.

BUT WHEN WE LOOK AT THE SCENE PHOTOGRAPHS, I CAME UP WITH AN EXCELLENT EXPLANATION FOR THAT.

Christie: LEE KNEW THAT THE LONG GRASS WAS THE KEY.

IT'S THE KIND OF PLACE WHERE BLOWFLIES LIKE TO SLEEP.

ALTHOUGH THEY RARELY FLY AT NIGHT, THEY WOULDN'T HAVE IGNORED THE SMELL OF FRESH FLESH DUMPED RIGHT ON THEIR DOORSTEP, AND COULD EASILY HAVE CRAWLED THEIR WAY TOWARDS IT.

SO THE FLIES' BEHAVIOR DIDN'T RULE OUT LEE'S ESTIMATE.

BUT WAS HE RIGHT?

Goff: AS IT TURNED OUT, AS I WAS PHONING THIS IN, THEY HAD A SUSPECT WHO WAS CONFESSING TO HAVING PARTICIPATED IN THE DEATH.

AND HE ACTUALLY PLACED THE TIME OF DEATH AT 10:30 P.M., 3.5 DAYS PRIOR TO THE DISCOVERY OF THE BODY.

Christie: BULL'S-EYE.

AND MORE PROOF THAT THE FLY CLOCK RARELY LIES.

FORENSIC ENTOMOLOGY, THE USE OF INSECTS TO HELP SOLVE CRIMES, HAS BEEN PRACTICED FOR CENTURIES.

IT WAS FIRST RECORDED IN CHINA IN 1235 WHEN FLIES WERE USED TO DETECT A BLOODY MURDER WEAPON, ALTHOUGH THE LINK BETWEEN FLY EGGS AND MAGGOTS WASN'T DISCOVERED UNTIL 1688.

IN THE WESTERN WORLD, FORENSIC ENTOMOLOGY WAS BORN IN 1855, WHEN A FRENCH DOCTOR USED HIS KNOWLEDGE OF INSECTS TO HELP THE PARISIAN POLICE SOLVE THE MURDER OF A CHILD.

NOW THERE ARE THOUSANDS OF FORENSIC SCIENTISTS AROUND THE WORLD.

THEY'RE AN ESSENTIAL PART OF THE MODERN DAY LAW ENFORCEMENT MACHINE.

THERE ARE ALL KINDS OF WAYS THAT INSECT WITNESSES CAN TRAP A KILLER.

BACK AT THE SCENE OF OUR DOUBLE MURDER, LET'S SEE HOW THE EVIDENCE IS PILING UP.

AS WE'VE SEEN, EVEN JUST A FEW MAGGOTS CAN GIVE CRUCIAL TESTIMONY TO THE TIMING OF A MURDER.

HERE, SOME 20,000 ARE AT WORK ON THE VICTIM.

BUT MAGGOTS ARE NOT THE ONLY ANIMALS THAT VISIT THIS CORPSE.

THESE CAMERAS HAVE BEEN WATCHING OUR EXPERIMENTAL PIG AND HAVE RECORDED MANY OTHER VISITORS.

NOT ALL THESE CREATURES WILL HELP THE POLICE.

SOME HAVE TAMPERED WITH THE EVIDENCE.

CROWS GOUGE OUT EYE SOCKETS WHICH FALSELY SUGGESTS THAT THE VICTIM HAD BEEN BLINDED BEFORE DEATH.

A BUZZARD CAN LEAVE MARKS THAT LOOK SUSPICIOUSLY LIKE STAB WOUNDS.

DOGS AND FOXES CRUSH BONES TO REACH THE JUICY MARROW INSIDE.

HEDGEHOGS, ON THE OTHER HAND, ARE ATTRACTED BY SOMETHING ELSE -- THE MAGGOTS THEMSELVES.

RATS LEAVE GNAW MARKS THAT CAN SUGGEST A BEHEADING.

SO ALTHOUGH ANIMALS DO HELP, THEY CAN ALSO HINDER INVESTIGATIONS.

TO LEARN MORE, SCIENTISTS GO BEYOND USING PIGS.

IN KNOXVILLE, TENNESSEE, A PROGRAM USING DONATED HUMAN REMAINS HAS HELPED SOLVE OVER A HUNDRED MURDERS.

IT'S CALLED THE BODY FARM.

I BEGAN THIS PROJECT ABOUT 25 YEARS AGO, TRYING TO DETERMINE IN A SCIENTIFIC MANNER HOW LONG IT TAKES FOR BODIES TO DECAY.

NOW, YOU CAN USE PIGS AS A MODEL.

HOWEVER, WHEN WE LOOK AT THE HUMAN BODY, WE'RE LOOKING AT THE HANDS AND THE FEET, AND THESE ARE SOMETHING THAT PIGS DON'T HAVE.

SO WE'RE TRYING TO RECORD EVERYTHING THAT CHANGES IN A HUMAN IN THE DECAY PROCESS.

Christie: AMAZINGLY, THERE IS A WAITING LIST OF PEOPLE WHO'VE DONATED THEIR OWN BODIES FOR THIS RESEARCH.

THE EXPERIMENTS THEY DO HERE ARE EXACTLY LIKE THOSE DONE WITH PIGS, EXCEPT HERE, THE CAMERAS RECORD VISITORS TO HUMAN BODIES.

WE'RE RECORDING VIDEO ON THE WILDLIFE THAT COME INTO THE FACILITY AT NIGHT.

WE HAVE A WOODEN FENCE AND A WIRE FENCE THAT KEEP OUT THE LARGER ANIMALS, SUCH AS DOGS AND COYOTES.

BUT WE'RE PRIMARILY INTERESTED IN THE SMALL MAMMALS THAT COME INTO THE FACILITY.

WE HAVE RACCOONS, OPOSSUMS, AND RATS, AND WHAT WE'RE FINDING IS THAT ALL OF THESE ANIMALS ARE VERY INTERESTED IN THE MAGGOTS.

WE FIND THE RACCOONS ARE DIGGING IN THE DIRT AT NIGHT.

OPOSSUMS ARE EATING MAGGOTS.

WE'RE SEEING RATS EVEN DIGGING IN THE DIRT SOME AND EATING THE MAGGOTS.

RACCOONS, WHEN THEY COME ACROSS CARRION IN THE WOODS, THEY'LL MAKE AN ENTRY HOLE.

AND ONCE THEY'VE MADE THAT ENTRY HOLE, THEN FLIES WILL LAY THEIR EGGS.

THE EGGS WILL HATCH THEN INTO MAGGOTS.

NIGHT AFTER NIGHT, THE RACCOONS WILL COME BACK, AND THEY'LL USE THEIR HANDS AND PROBE UP INTO THAT ENTRY AND PULL THE MAGGOTS OUT OF THE BODY.

IT'S SOMETHING WE WEREN'T EXPECTING.

AND THEY SPEND A LOT OF TIME DOING THAT.

Christie: BROWN RATS ALSO LOVE BONES.

AND ONE OF THE THINGS THAT RATS WILL DO IS, THEY'LL CHEW INTO A LONG BONE, FOR EXAMPLE -- THIS IS YOUR LOWER SHIN BONE.

YOU CAN SEE THAT THE BONE HAS A LOT OF LITTLE CELLS IN IT.

AND THESE LITTLE CELLS ARE CHOCKFUL OF FAT.

THE RATS HAVE A TENDENCY TO GO AFTER THAT FAT WHERE THE BONE IS REAL THIN.

AND IT ENDS UP LOOKING VERY MUCH LIKE THIS.

THEY'LL DO THIS VERY SOON AFTER A PERSON HAS DIED AND THE FLESH HAS GONE AWAY.

Christie: BILL RODRIGUEZ TRAINED AT THE BODY FARM.

NOW HE PUTS WHAT HE LEARNED INTO PRACTICE, HELPING POLICE UNDERSTAND ANIMAL DAMAGE AND CLEARING UP THE CONFUSION THESE CREATURES CAN CAUSE.

Rodriguez: FOR EXAMPLE, DOWN HERE ALONG THE AREA OF THE FEET, WE SEE THAT THERE'S EVIDENCE THAT THE TOES ARE MISSING AND HAVE BEEN CHEWED ON BY THINGS SUCH AS COYOTES, DOGS, THIS CAN BE MISINTERPRETED MANY TIMES AS SOME TYPE OF BLUNT FORCE INJURY TO THE FEET.

WE HAVE EVIDENCE OF HOLES IN SOME OF THE MUMMIFIED TISSUE AND TEARING.

THIS IS ACTUALLY THE RESULT OF BUZZARDS... THAT WILL ACTUALLY FEED AND TEAR AT THE TISSUE AND PRODUCE THIS VERY SINUOUS TYPE STRAND FORM.

THIS, MANY TIMES, CAN ALSO BE MISINTERPRETED AS SOME TYPE OF STABBING OR CUTTING OF THE TISSUES BY A KNIFE.

WE ALSO HAVE EVIDENCE OF SOME CARNIVORE DAMAGE UP ALONG HERE IN THE AREA OF THE PELVIS.

A RESULT OF DOG OR COYOTES THAT HAVE BEEN CHEWING.

THIS MAY BE MISINTERPRETED AS SOME TYPE OF BLUNT FORCE INJURY.

AND EVEN UP ON THE SKULL HERE, THERE'S EVIDENCE THAT RODENTS HAVE COME AND CHEWED ON AREAS OF THE SKULL.

THIS CAN BE MISTAKEN AS DECAPITATION OR CUT MARKS.

AND WE EVEN HAVE SOME DAMAGE TO THE ORBITS OF THE EYES.

VULTURES AND CROWS LIKE TO EAT VERY THE SOFT TISSUES AND PICK AT THE AREAS OF THE EYE ORBIT.

THEY DAMAGE MANY OF THE DELICATE BONES.

THAT CAN BE EASILY MISINTERPRETED AS AN INJURY PRODUCED BY HUMANS.

Christie: ALL THIS EXPERTISE IS WORKING AGAINST OUR SUSPECT IN THE DOUBLE PIG MURDER.

FALSE EVIDENCE WON'T COVER HIS TRACKS.

JUST OFF VANCOUVER, SCIENTISTS ARE INVESTIGATING WHAT HAPPENS TO A BODY UNDERWATER.

WHAT STRANGE CREATURES VISIT A CORPSE DOWN HERE?

A GIANT OCTOPUS HAS EIGHT ARMS TO EMBRACE THE VICTIM.

THIS PROJECT IS THE BRAINCHILD OF PROFESSOR GAIL ANDERSON AT SIMON FRASER UNIVERSITY IN VANCOUVER.

Anderson: THESE EXPERIMENTS HAVE BEEN INCREDIBLY USEFUL BECAUSE NOW WE CAN ACTUALLY UNDERSTAND A LOT MORE THAN IT IS ON LAND.

AND THERE'S A LOT MORE STUDIES WE NEED TO DO TO BE ABLE TO EXPAND OUR KNOWLEDGE IN THIS AREA.

BUT CERTAINLY IT'S TOLD US A LOT ABOUT THE ANIMALS THAT COLONIZE, LIKE SEA STARS AND SHRIMP AND CRABS AND ALSO SORT OF OTHER PREDATORS THAT WOULD COME IN LIKE AN OCTOPUS, FISH, THINGS LIKE THAT.

HERE YOU CAN SEE THESE ENORMOUS SUN STARS BEING ATTRACTED TO THE BODY.

AND THEY'RE REALLY JUST GOING TO GRAZE AND SCAVENGE.

BUT WHAT THEY DO IS, THEY ALMOST ENVELOPE THE WHOLE PIG.

YOU CAN BARELY SEE THE CARCASS WHEN THERE'S ONE OR TWO OF THESE ANIMALS ON IT.

AND THEY KIND OF RASP THE SKIN.

THEY KIND OF HAVE SORT OF A SANDPAPERY KIND OF ACTION ON THE SKIN BY RASPING MOUTH PARTS.

AND THEY CREATE THESE LARGE SORT OF ROUND SORT OF GRAZED WOUNDS, WHICH COULD, TO THE UNEDUCATED EYE, LOOK LIKE A WOUND THAT MAYBE HAPPENED IN LIFE.

PERHAPS THE PERSON WAS INJURED, TORTURED.

AND, OF COURSE, THAT'S NOT TRUE.

IT'S AN ARTIFACT CREATED BY THE ANIMALS.

BUT WE DO HAVE TO BE ABLE TO UNDERSTAND THIS SO THAT WE KNOW AND CAN INTERPRET THIS PROPERLY FOR THE COURTS AND FOR THE FAMILIES.

Christie: OUR SCIENTIST SUSPECT THINKS HE'S COMMITTED THE PERFECT MURDER.

BUT EXPERTS ARE SIFTING THROUGH THE EVIDENCE, DISTINGUISHING BETWEEN FACT AND FICTION.

HOW WILL THEY LINK HIM TO THE SCENE OF THE CRIME?

WHEN IT COMES TO LOCATION, THE BEST WITNESSES AREN'T ALWAYS ANIMALS.

DAVID HALL HAS STUDIED PLANTS FOR MORE THAN 30 YEARS.

IDENTIFYING WHERE THEY COME FROM IS THE KEY TO MANY A CASE.

Hall: THERE ARE 300,000 DIFFERENT KINDS OF PLANTS IN THE WORLD.

JUST LIKE ANIMALS, THEY CAN HAVE IMPORTANT FORENSIC USES.

PLANTS GROW IN NICHES.

THAT IS, THEY SOMETIMES GROW IN A PARTICULAR KIND OF HABITAT SUCH AS A SWAMP OR UP ON A SAND HILL.

THE PLANT GROWING IN A SWAMP, OBVIOUSLY, WOULD NOT USUALLY BE FOUND ON A SAND HILL OR IN A DRY, VERY DRY HABITAT.

AND OBVIOUSLY THAT IF A PLANT THAT IS FROM A DIFFERENT KIND OF HABITAT IS FOUND ON A SUSPECT OR A BODY, IT HAS A VERY STRONG LINK OR SOMETIMES CAN ABSOLUTELY LINK A SUSPECT OR THE VEHICLE TO THE SCENE OF THE CRIME.

A RECENT CASE THAT I HAD INVOLVED A VERY EXPENSIVE GOLF COURSE.

SOMEONE HAD DRIVEN A VEHICLE OUT ONTO THE GOLF COURSE.

APPARENTLY HE HAD SPUN HIS TIRES, DROVE BIG LAZY CIRCLES, ALSO HAD DAMAGED A GREEN.

LAW ENFORCEMENT WAS CALLED, AND THEY FOUND A SUSPECT VEHICLE NEARBY.

WHEN I EXAMINED THE GRASS FRAGMENTS, I WAS ABLE TO IDENTIFY IT AND MATCH IT TO BERMUDA GRASS.

BECAUSE THE BERMUDA GRASS PIECES WERE ENTIRE GRASS PLANTS THAT WERE ONLY A FRACTION OF AN INCH TALL, IT PROVED TO BE A VERY EXPENSIVE GRASS FOUND ONLY ON ESTATES AND GOLF COURSES.

I ALSO FOUND VERY SHARP, VERY CLEAN-CUT SURFACES.

SO IT HAD BEEN CUT WITH A VERY SHARP, WELL-MAINTAINED BLADE.

THIS DOES NOT HAPPEN ON ROADSIDES.

THE SUSPECT COULD NOT EXPLAIN HOW THIS BERMUDA GRASS GOT ON HIS CAR.

WITH THIS VERY STRONG PLANT EVIDENCE, HE WAS FOUND GUILTY.

Christie: EVEN A PARTICLE OF POLLEN CAN BLOW THE WHISTLE.

POLLEN GRAINS ARE THE REPRODUCTIVE STRUCTURES OF HIGHER PLANTS.

AND THEY'RE MICROSCOPIC FOR THE MOST PART, VERY SMALL.

YOU COULDN'T SEE T. SOME PLANTS PRODUCE RELATIVELY SMALL QUANTITIES.

THE INSECT-POLLINATED ONES.

AND THEN SOME, LIKE A PINE TREE, MAY PRODUCE A HUNDRED MILLION ON A BRANCH.

WHEN YOU MAGNIFY THEM UNDER A MICROSCOPE, YOU CAN SEE VARIOUS KINDS OF FEATURES, SPINES, AND OPENINGS, AND SIZE DIFFERENCES.

AND CAN THEN COMPARE THEM TO SEE IF WE CAN IDENTIFY THE EXACT SPECIES THAT MAY HAVE BEEN INVOLVED IN A CRIME.

Christie: ONE MURDERER DISPOSED OF HIS WIFE'S BODY NEAR THEIR HOME IN WASHINGTON STATE.

EVERYONE THOUGHT HE WAS IN CALIFORNIA ON A BUSINESS TRIP, BUT HE HAD SECRETLY RACED HOME TO CARRY OUT THE MURDER.

THE DEED DONE, HE SPED BACK TO HIS BUSINESS MEETINGS, USING THEM AS AN ALIBI.

HE TAMPERED WITH THE ODOMETER ON HIS RENTAL CAR.

ERASING THE MILES HE'D ACCUMULATED DRIVING HOME.

BUT THE POLICE WERE STILL SUSPICIOUS, AND A FORENSIC BOTANIST WAS CALLED IN TO CHECK THE CAR.

A POLLEN SAMPLE FROM THE AIR FILTER WAS IDENTIFIED AS COMING FROM A PLANT THAT GREW ONLY IN WASHINGTON STATE.

THIS MICROSCOPIC WITNESS TIED THE KILLER TO THE CRIME SCENE.

BUT RECENTLY, PLANT EVIDENCE HAS BEEN GETTING EVEN MORE SOPHISTICATED.

DNA FINGERPRINTING HAS BEEN USED TO IDENTIFY PEOPLE FOR YEARS.

BUT NOW THE SAME TECHNIQUE CAN BE USED ON PLANTS.

DNA FROM SOME PLANT SPECIES CAN BE ANALYZED TO GIVE A GENETIC CODE UNIQUE TO THE INDIVIDUAL PLANT.

BY READING THE DNA OF SOME FRUITS AND SEEDS, THEY CAN BE LINKED RIGHT BACK TO THE EXACT PLANT THEY ORIGINALLY CAME FROM.

IN ARIZONA, A MURDER SUSPECT DUMPED A BODY AT AN OLD FACTORY AND BACKED HIS PICKUP TRUCK INTO A PALO VERDE TREE.

WHEN HE DID, SOME SEED PODS FELL INTO THE BACK OF THE TRUCK.

IN THIS DNA FINGERPRINT CASE, BOTANISTS MATCHED THESE SEED PODS TO THE EXACT TREE AT THE SCENE.

THE SUSPECT WAS FOUND GUILTY OF MURDER AND IS NOW SERVING LIFE IN PRISON.

Christie: USING THIS APPLE'S DNA AND THE TREE POLLEN ON HIS CAR, POLICE ARE CLOSING IN ON OUR SUSPECT, TOO.

BUT WHAT ABOUT THE SECOND BODY?

DIATOMS ARE MICROSCOPIC PLANTS, JUST SINGLE CELLS.

SOME FLOAT, OTHERS PRODUCE SLIME ON WHICH THEY GLIDE.

THEY'RE FOUND IN WATER EVERYWHERE.

IN LONDON, A MURDER INVESTIGATION RELIED ON CRITICAL EVIDENCE FROM DIATOM EXPERT NIGEL CAMERON.

RECENTLY I WAS ASKED TO BE INVOLVED IN A MURDER CASE IN THE SOUTHWEST OF ENGLAND WHERE A MAN WAS ACCUSED OF DROWNING HIS WIFE IN A RIVER.

HER BODY WAS FOUND AT A PARTICULAR POINT IN THE RIVER.

HE DENIED FIRSTLY HAVING BEEN IN THE RIVER AT ALL, AND CERTAINLY DENIED BEING IN THAT STRETCH OF RIVER.

HOWEVER, THE POLICE HAD THE MAN UNDER SURVEILLANCE AND SAW HIM TRYING TO DISPOSE OF SOME CLOTHING.

THE POLICE RECOVERED THESE ITEMS.

AND I WAS SENT SAMPLES OF CLOTHING.

AND I WAS THEN ABLE TO PREPARE THESE SAMPLES, USING STRONG PEROXIDE.

SO I WAS LEFT WITH THE CLEAN SHELLS OF DIATOMS.

Christie: THESE BOXES OF SILICA ARE OBJECTS OF GREAT BEAUTY.

THE INTRICATE PATTERNS TELL ONE KIND FROM ANOTHER.

AND WITH MORE THAN 200,000 SPECIES WORLDWIDE, THE PROBLEM FOR CRIMINALS IS THAT DIFFERENT KINDS LIVE IN VERY SPECIFIC PLACES.

Cameron: BEFORE THE TRIAL, I ALSO LOOKED AT SAMPLES FROM UPRIVER, DOWNRIVER, AND SITE OF THE DROWNING.

THE BEST MATCH FOR THE DIATOMS FOUND ON THE MAN'S CLOTHING WAS FOUND TO BE THE STRETCH WHERE THE WOMAN'S BODY WAS FOUND.

SO THIS PROVIDED EVIDENCE THAT THE MAN HAD BEEN IN THE WATER AT THE VERY POINT WHERE THE BODY WAS FOUND.

THE MAN WAS SUBSEQUENTLY CONVICTED ON THE BASIS OF DIATOM AND OTHER EVIDENCE OF THE MURDER OF HIS WIFE, AND HE'S NOW SERVING A LIFE SENTENCE.

Christie: SO SINGLE CELLS COULD LEAD DIRECTLY TO A PRISON CELL.

AT LEAST OUR SUSPECT REMEMBERED TO DESTROY THE MURDER WEAPON.

SYDNEY, AUSTRALIA.

A FIRE TEARS THROUGH A WAREHOUSE.

HOW DID IT START?

TO FIND OUT, THE FIREFIGHTERS USE THEIR SECRET WEAPON.

ELLIE HAS EXTRAORDINARY POWERS.

WITH WELL OVER 100 MILLION SMELL RECEPTORS, HER NOSE IS FAR MORE SENSITIVE THAN OURS.

SHE'S THE ONLY CANINE IN AUSTRALIA SPECIALLY TRAINED TO SNIFF OUT GASOLINE, WHICH IS OFTEN USED TO START FIRES.

THIS TIME, IT WASN'T ARSON.

BUT LET'S DO A TEST TO SEE WHAT ELLIE'S SUPER SENSITIVE NOSE CAN DO.

A TINY DROP OF GAS IS PLANTED AT THE SCENE.

IT SEEMS AN IMPOSSIBLE CHALLENGE.

CAN ELLIE SNIFF IT OUT?

A DOG SNIFFS UP TO SEVEN TIMES A SECOND.

AND THE AIR BLOWN BACK OUT IS EXTRA HUMID, RE-CONCENTRATING MOLECULES OF SMELL RIGHT IN FRONT OF THE NOSE.

Man: FIND IT, FIND IT.

THAT A GIRL, WHERE IS IT?

FIND IT.

Christie: ONCE SHE HITS THE SPOT, SHE'S TRAINED TO SIT AND MARK IT WITH HER PAW.

Man: THAT A GIRL!

YOU SHOW ME THE EXACT SPOT.

YOU SHOW ME IT, YOU SHOW ME.

THAT A GIRL!

THAT'S MY GIRL.

THAT A GIRL.

GOOD GIRL, ELLIE.

THAT A GIRL.

GOOD GIRL.

ELLIE WAS, WHEN SHE FIRST STARTED WITH US, ELLIE WAS THAT ACCURATE AND THAT SKILLED.

WE HAD A LARGE FACTORY FOR HER.

WHEN ELLIE WAS FINISHED SEARCHING ON HER WAY BACK TO THE CAR, SHE ACTUALLY ALERTED AT A WINDOWSILL.

AND WHEN WE CLEARED IT OUT, THAT'S WHERE THE PETROL HAD BEEN POURED.

SO IN ACTUAL FACT, ELLIE WAS THE ONLY ONE WHO WAS ABLE TO DETECT THAT THAT WAS AN ARSON JOB.

SO SHE'S VERY WELL SKILLED.

AND TO BE ABLE TO FIND A MARKER IN A FACTORY LIKE THIS, SHE'S A VERY ACCURATE DOG.

THAT'S MY GIRL.

GOOD GIRL.

WHO'S A GOOD GIRL?

YOU ARE.

Christie: SO ELLIE COULD HAVE EASILY FOUND OUR MURDER WEAPON.

BUT IN ITS CHARRED CONDITION, COULD IT BE OF ANY USE TO THE POLICE?

REGIS MILLER WORKS AT THE FOREST PRODUCTS LABORATORY IN MADISON, WISCONSIN.

IT'S HOME TO THE WORLD'S LARGEST COLLECTION OF WOOD, MORE THAN 100,000 SAMPLES FROM 18,000 SPECIES OF TREES.

THE INTERNAL STRUCTURE OF WOOD CAN BE AS DISTINCTIVE AS A FINGERPRINT.

SOME, LIKE THIS BLACK LOCUST WOOD, GLOW EERILY IN ULTRAVIOLET LIGHT.

WHILE OTHER SPECIES CAN DYE WATER BLUE.

COULD REGIS HELP TO NAIL THE SCIENTIST FROM A FRAGMENT OF CHARRED WOOD?

HE'S DONE IT BEFORE.

THERE WAS A YOUNG LADY WHO WAS BEATEN TO DEATH.

THE POLICE FOUND A VERY SMALL SPLINTER IN HER HEAD.

THEY ALSO HAD SOME SUSPECTS IN MIND.

AND SOMEONE HAD SEEN THEM THROW AWAY A POOL CUE IN A DUMPSTER.

THE POLICE WERE HOPING THAT I COULD LOOK AT THE POOL CUE AND THE SMALL SPLINTER AND SEE IF THEY WERE IN FACT THE SAME SPECIES.

I NEEDED TO MAKE A MICROSCOPE SLIDE.

I LOOKED FOR LONG, THIN CRYSTALS IN BOTH THE SPLINTER AND IN THE POOL CUE.

AND I DID FIND THEM IN BOTH.

THIS CONVINCED ME THAT THEY WERE BOTH FROM THIS TROPICAL HARDWOOD CALLED RAMIN.

I TESTIFIED IN COURT THAT THE POOL CUE AND THE SPLINTER WERE THE SAME SPECIES.

AND SUBSEQUENTLY, THE SUSPECTS WERE CONVICTED OF MURDER.

Christie: REGIS DID IT AGAIN IN THE CASE OF THE SAWED-OFF SHOTGUN.

Miller: A FEW YEARS AGO, CALIFORNIA POLICE FOUND A SAWED-OFF SHOTGUN IN A MAN'S CAR.

THE GUY CLAIMED THE GUN WASN'T HIS.

BUT THE POLICE SEARCHED HIS HOUSE AND FOUND A PIECE OF WOOD THAT LOOKED LIKE IT DID COME FROM THE SHOTGUN.

THE SUSPECT WAS A CONVICTED FELON, WHICH MEANT THAT HE WOULD GO TO PRISON FOR A VERY LONG TIME IF HE WAS FOUND GUILTY OF POSSESSION OF A FIREARM.

THE POLICE BROUGHT THE SHOTGUN AND THE PIECE OF WOOD TO ME TO SEE IF COULD MATCH THEM UP.

I MADE PHOTOGRAPHS OF BOTH PIECES.

THE GRAIN PATTERNS MATCHED EXACTLY, PROVING THAT THE PIECE FROM THE MAN'S HOUSE CAME FROM THE GUN.

WHEN THE EVIDENCE CAME TO COURT, THE FELON WAS FOUND GUILTY AND SENTENCED TO LIFE.

Christie: A TREE CAN HELP IDENTIFY A GUN.

CAN ANIMALS HELP IDENTIFY A BULLET?

GUNSHOT WOUNDS AREN'T ALWAYS OBVIOUS ON A BADLY DECOMPOSED BODY.

AND IF THE BULLET'S PASSED CLEAN THROUGH AND BEEN LOST, THEN INVESTIGATORS MAY NOT BE ABLE TO TELL IF A GUN'S BEEN USED AT ALL.

BUT THIS EXPERIMENT SHOWS HOW MAGGOTS CAN HELP.

BULLETS LEAVE TINY TRACES OF HEAVY METALS IN FLESH THAT ARE UNDETECTABLE BY NORMAL MEANS.

BUT AS THE MAGGOTS FEED ON THE MEAT AROUND THE BULLET WOUND, THE METALS LEFT BEHIND ARE CONCENTRATED IN THEIR BODIES.

SADLY, THIS WILL BE THE MAGGOTS' LAST MEAL.

AFTER DINNER, THEY'RE UNCEREMONIOUSLY DUMPED IN A BATH OF ACID.

THEN THE LIQUID IS BOMBARDED BY A LASER BEAM.

THE ANALYSIS REVEALS THREE HEAVY METALS FROM THE BULLET -- ANTIMONY, BARIUM, AND LEAD, PROOF OF A SHOOTING.

IT SEEMS THERE'S NO LIMIT TO THE CUNNING VERSATILITY OF THE MAGGOT.

AND TO PROVE IT, THE FBI HAS ENGAGED IN SOME BIZARRE EXPERIMENTS WITH EXPLOSIVE CHARGES.

THIS EXPERIMENT IS DESIGNED TO REPLICATE THE EFFECT OF A TERRORIST BOMB.

IT'S VITAL FOR INVESTIGATORS TO DETERMINE THE TYPE OF EXPLOSIVE USED.

THAT CAN LEAD DIRECTLY TO THE BOMB-MAKERS.

ONCE AGAIN, IT'S MAGGOTS TO THE RESCUE.

BILL RODRIGUEZ IS WORKING ON THE TRIALS.

THE MAGGOTS ARE GROUND UP FOR ANALYSIS.

BILL'S EXPERIMENTS HAVE SHOWN THAT AS THEY FEED ON THE CONTAMINATED MEAT, THE MAGGOTS CONCENTRATE EXPLOSIVE RESIDUES IN THEIR BODIES.

AND IT'S MUCH EASIER TO ANALYZE THE MAGGOTS THAN THE ORIGINAL MEAT.

WITHOUT THE MAGGOTS, THIS VITAL ANALYSIS WOULD NOT BE POSSIBLE.

THE TERRORISTS ARE ONE STEP CLOSER TO BEING CAPTURED.

Rodriguez: I'M CERTAINLY SEEING A SIGNATURE THAT IS DEFINITELY SHOWING SOME RELATIONSHIP TO THE TNT.

THERE'S SOME SILVER.

Christie: IMAGINE YOU'RE WITH AN ANTI-TERRORIST SQUAD OUTSIDE A TERRORIST BOMB FACTORY.

YOU DON'T WANT TO SEND YOUR AGENTS IN WITHOUT EVIDENCE.

WHAT YOU NEED IS A TEAM OF SPIES SO SMALL THAT NO ONE WILL EVEN NOTICE THEM.

A TINY DETECTIVE GETS A BATH IN EXPLOSIVES.

HAIR ON THE FLY'S BODY AND STATIC ELECTRICITY ON ITS LEGS MEANS THAT THE EXPLOSIVE POWDER STICKS ALL OVER IT.

THE INSECTS CAN BE THE TIP-OFF THE AGENTS NEED.

FLIES CAN LITERALLY PROVIDE A WHOLE BODY OF EVIDENCE.

IF THE EXPLOSIVE TESTS PROVE POSITIVE, AGENTS HAVE THE CRUCIAL CONFIRMATION THEY NEED BEFORE EXECUTING A RAID.

FLIES HAVE HELPED THEM TO PREVENT A TERRORIST ATROCITY.

IT'S ALMOST A YEAR SINCE OUR VICTIM WAS DUMPED IN THE WOODS.

BUT EVEN IF A BODY IS FOUND MONTHS OR YEARS AFTER A MURDER, NATURE CAN STILL TRACK THE KILLER.

THE PIG IS DRIED UP AND SHRIVELED NOW.

BUT THERE'S AN INSECT THAT LOVES TO FEED ON TOUGH OLD FLESH.

THESE ARE WOOLLY BEARS.

THEY ARE THE LARVAE OF DOMESTIC BEETLES.

THEY RARELY VISIT A CORPSE LESS THAN FOUR MONTHS OLD, SO EVEN AT THIS LATE STAGE, THESE ANIMALS CAN HELP TO DATE THE MURDER.

OUR CAMERAS HAVE BEEN CATCHING OTHER VISITORS, TOO.

FIELD VOLES USE LEFTOVER BONES TO KEEP THEIR TEETH SHARP.

BLUE TITS COLLECT HAIR AS A SOFT LINING FOR THEIR NEST.

ALL THIS ACTIVITY WOULD SEEM TO HELP THE MURDERER, AS HAIR AND BONES CAN IDENTIFY A CORPSE.

BUT PERHAPS THESE ANIMALS AREN'T SO MUCH DESTROYING THE EVIDENCE AS PUTTING IT AWAY IN A SAFE PLACE, AS LONG AS THE INVESTIGATORS KNOW WHERE TO SEARCH FOR IT.

BILL RODRIGUEZ IS LOOKING FOR CLUES.

HAIR COLOR AND LENGTH ARE VITAL AIDS IN IDENTIFYING A VICTIM.

ALL TOO OFTEN, HAIR IS MISSING FROM A LONG-DEAD BODY.

BUT BY SEARCHING BIRDS' NESTS, EVIDENCE CAN BE UNCOVERED THAT WOULD OTHERWISE HAVE BEEN LOST.

BILL KNOWS THE HIDING PLACES OF OTHER LITTLE THIEVES.

SEARCHING RODENT DENS SUCH AS MICE OR VOLES CAN BE ALSO VERY IMPORTANT FOR FORENSIC INVESTIGATION.

MANY TIMES SOME OF THE SMALL BONES OF THE HAND, AS WELL AS THE FEET ARE TAKEN BY THE RODENTS.

MANY OF THE RODENTS LIKE VERY SHINY ITEMS, SO THEY WOULD TAKE JEWELRY FROM THE BODY, INCLUDING RINGS.

A COUPLE OF OCCASIONS, WE FOUND AN ACTUAL BULLET THAT WAS RESPONSIBLE FOR THE DEATH OF THE INDIVIDUAL.

Christie: WHAT ABOUT LARGER RODENTS THAT ARE ATTRACTED TO OLD BONES?

EVEN SQUIRRELS CAN BE A PART OF THE INVESTIGATING TEAM.

Klippel: WE'RE FAIRLY INTERESTED IN WHAT SQUIRRELS DO ON BONE, WHAT IT MIGHT TELL US ABOUT TIME SINCE DEATH.

THIS IS AN EXAMPLE OF A FEMUR, AN UPPER LEG BONE, OF A HUMAN THAT HAS BEEN IN THE WOODS FOR AT LEAST A YEAR WHERE THE SQUIRRELS HAVE ACTUALLY STARTED TO GNAW IT.

AND ONE OF THE THINGS WE FIND IS THAT SQUIRRELS HAVE A TENDENCY TO CHEW BONE WHERE IT'S THE THICKEST.

PROBABLY NOT UNTIL THE BONE IS COMPLETELY DRY, THE GREASE IS COMPLETELY OUT OF IT.

AND TO SET UP AN EXPERIMENT TO SEE IF THAT WORKS, WE TOOK A DRY HUMAN CLAVICLE ON THIS LOG, ATTACHED IT SO THE SQUIRREL DIDN'T RUN AWAY WITH IT.

WE ATTACHED A GREASY CLAVICLE OVER HERE.

AND IT TOOK THE SQUIRRELS ABOUT TWO WEEKS TO FIND THIS AND ACTUALLY START GNAWING ON IT.

AND THIS ONE THAT WAS STILL GREASY WHEN WE PUT IT OUT, THEY HAVEN'T GNAWED ON IT AT ALL YET.

SO WE'RE FAIRLY SURE THAT SQUIRRELS IN FACT WILL AVOID BONE UNTIL THE GREASE IS COMPLETELY GONE OUT OF IT.

IF YOU FIND BONE THAT HAD BEEN SQUIRREL GNAWED, YOU'RE PRETTY SURE THAT YOU'RE DEALING WITH SOMEBODY THAT HAS DIED AT LEAST EIGHT MONTHS AGO.

Christie: OVER IN HAWAII, LEE GOFF WORKED WITH JUST BARE BONES AND INSECTS IN ONE OF HIS MOST INTRIGUING CASES.

IT ALL BEGAN WHEN A TIPSY DRIVER SPOTTED AN ABANDONED TOOLBOX BY THE SIDE OF THE ROAD.

BUT INSTEAD OF TOOLS, HE DISCOVERED A SEVERELY DECOMPOSED BODY.

THE TOOLBOX WAS TAKEN TO THE MORGUE WHERE INVESTIGATORS WERE IN FOR AN UNPLEASANT SURPRISE.

ALMOST IMMEDIATELY, THEY WERE ATTACKED BY ANGRY ANTS.

LEE SOON FOUND THE SOURCE.

INCREDIBLY, THERE WAS A NEST INSIDE THE SKULL.

COULD THE ANTS' LIFE CYCLE PROVIDE CLUES TO WHEN THE VICTIM IN THE TOOLBOX HAD DIED?

THE SPECIMENS OF THE LONG-LEGGED ANT COLLECTED FROM THE TOOLBOX IN THIS CASE SHOWED THAT WE HAD REPRODUCTIVE FORMS PRESENT.

TYPICALLY, FOR THIS SPECIES IN HAWAII, IT REQUIRES ABOUT 12 MONTHS BETWEEN THE TIME THE COLONY IS INITIATED UNTIL THE WINGED REPRODUCTIVES BEGIN TO APPEAR AND YOU HAVE FLYING ANTS.

Christie: THERE WAS ANOTHER VALUABLE CLUE -- THE EMPTY PUPA CASE OF A SOLDIER FLY.

THE LIFE CYCLE OF THESE FLIES IS THREE MONTHS.

BUT THEIR MAGGOTS WOULD NOT HAVE SURVIVED ALONGSIDE VORACIOUS ANTS.

SO THE MAGGOT MUST HAVE COMPLETED ITS LIFE CYCLE BEFORE THE ANTS ARRIVED.

Goff: SO WE NOW HAVE THREE MONTHS FOR THE FLIES TO COMPLETE THEIR DEVELOPMENT, FOLLOWED BY A 12-MONTH PERIOD BETWEEN THE TIME THE COLONY OF ANTS WAS ESTABLISHED.

THIS GAVE US A TOTAL OF 15 MONTHS.

Christie: A TIME OF DEATH MEANT THE POLICE COULD ZERO IN ON A SUSPECT.

HE MIGHT HAVE GOTTEN AWAY SCOT-FREE, BUT CONFRONTED WITH THE INSECT EVIDENCE, HE CONFESSED.

IN FLORIDA, A SKELETON WAS DISCOVERED IN THE WOODS.

THE POLICE TURNED TO FORENSIC BOTANIST DAVID HALL.

THE OLD BONES WERE DIFFICULT TO DATE.

BUT THE PLANTS GROWING UP THROUGH THE BONES WERE NOT.

Hall: THE REMAINS WERE TAKEN TO A FORENSIC ANTHROPOLOGIST, A BONE EXPERT, WHO DATED THEM AT APPROXIMATELY TWO YEARS.

THIS WAS PROBLEMATICAL BECAUSE THE CHIEF SUSPECT IN THE CASE WAS IN PRISON FOR THE LAST TWO YEARS.

VARIOUS ROOTS AND BRANCHES WERE FOUND AMONG THE SKELETONIZED REMAINS.

ONE OF THE BRANCHES WAS GROWING DIRECTLY THROUGH A HOLE IN THE BONE.

I WAS ABLE TO LOOK AT THE RINGS IN THIS BRANCH.

I FOUND FOUR GROWTH RINGS.

THIS MEANT THAT THE SKELETON HAD TO HAVE BEEN THERE FOR AT LEAST FOUR YEARS.

THIS PUT THE MURDER AT A TIME WHEN THE SUSPECT WAS OUT OF JAIL.

AND THE SUSPECT WAS FOUND GUILTY.

[ SIRENS BLARING ] Policeman: YOU'RE UNDER ARREST.

COME WITH US.

UP AGAINST THE CAR, PLEASE.

Christie: OUR SUSPECT'S CRIMES HAVE FINALLY CAUGHT UP WITH HIM.

ANIMALS AND PLANTS ARE READY TO TESTIFY.

IF HE'D REALLY MURDERED THOSE PIGS, HE'D NEVER HAVE GOTTEN AWAY WITH IT.

Policeman: IN THE BACK OF THE CAR, PLEASE.

Christie: FLIES WOULD HAVE FOUND THE BODY AND REVEALED THE TIME OF THE KILLING.

FRUIT COULD HAVE LINKED HIS CAR TO THE MURDER LOCATION.

AND THE TESTIMONY OF POLLEN WOULD HAVE BACKED THAT UP.

MICROSCOPIC DIATOMS COULD LINK HIM TO THE RIVER, TOO.

AND BURNING THE MURDER WEAPON WAS FAR FROM FOOLPROOF.

A DOG COULD HAVE SNIFFED IT OUT.

AND THE STRUCTURE OF WOOD WOULD HAVE BEEN THE FINAL NAIL IN THE SCIENTIST'S COFFIN.

THE SIMULATED MURDERS HAVE SERVED THEIR PURPOSE.

AND THE CAMERAS HAVE RECORDED THE EVENTS OF LIFE AFTER THE DEATH.

ALL THAT'S LEFT OF THE PIG NOW, A FEW SCRAPS OF CLOTHES AND A FEW BONES.

BUT REMEMBER, AFTER ALL WE'VE SEEN, IF YOU'RE THINKING OF COMMITTING A CRIME, THINK AGAIN.

THERE ARE ANIMAL AND PLANT WITNESSES EVERYWHERE.

THIS PROGRAM WAS MADE POSSIBLE BY THE CORPORATION FOR PUBLIC BROADCASTING AND BY CONTRIBUTIONS TO YOUR PBS STATION FROM VIEWERS LIKE YOU.