Who dunnit? Wildlife criminals beware: one lab uses high-tech tools and detective work to solve crimes against nature.

DID YOU KNOW?

* Created in 1973, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) is an agreement between world governments to prevent the trade of endangered wildlife. To help enforce CITES, the National Fish and Wildlife Forensics Laboratory was established in 1989. The lab helps to pinpoint criminals who illegally kill and trade animals.

* The first forensic science lab was created in France in 1865. 1! was called the Paris Institute for Forensic Science.

CRITICAL THINKING:

* Suppose you were the park ranger who stumbled upon the dead grizzly bear in Katmai National Park. What kinds of evidence would you try to find? For example, the shooter could have left behind a clothing fiber. Explain your reasoning.

CROSS-CURRICULAR CONNECTIONS:

ART: In parts of Africa, the poaching of elephants for their ivory tusks has decimated their population. Design a pamphlet, describing why elephants should be protected. Include drawings of the elephants.

RESOURCES

* Check out Court TV's "Forensics in the Classroom" for background information and standards-based activities: www.courttv.com/forensics_curriculum/

* This site has great forensics activities, including interactive mysteries: www.pbs.org/wgbh/nova/hotscience/int_fore.html

* Learn about the history of forensic science and more at: www.virtualmuseum.ca/Exhibitions/Myst/index.html

A group of hikers listens intently as naturalist Ken Day leads them through Alaska's Katmai National Park. Suddenly, they come to a halt. Lying on the ground in front of them is the carcass of a 225 kilogram (500 pound) grizzly bear--a species protected under the Endangered Species Act.

Why would someone illegally kill a protected animal? Globally, the illegal sale of wild animals and their body parts--from bear hides to elephant tusks--yields about $5 billion a year. The result is a further dwindling of already-at-risk species.

Nabbing the poachers who stalk these animals is critical to protecting wildlife. That requires the help of the U.S. Fish and Wildlife Service's Forensics Laboratory in Ashland, Oregon--the only lab in the world dedicated solely to solving wildlife crimes. The lab's top-notch experts handle more than 900 cases annually. Read on to learn how they use scientific sleuthing to crack cases.

WOLF DELIVERY

Evidence such as that from the killed Katmai bear often lands in the lab of Richard Stroud. As a veterinary medical examiner, or animal pathologist, Stroud examines animal carcasses linked to wildlife crimes. One by one, he gathers clues to re-create the details surrounding an animal's death.

So when Stroud received a package from a Minnesota park ranger containing the frozen carcass of a gray wolf, he suited up with latex gloves and a lab coat to perform a necropsy, or animal autopsy. Like most corpses he receives, this one came with a story: "The investigator who sent the carcass wanted me to determine whether or not the killer shot the wolf in self-defense," explains Stroud. A father and son had claimed that they'd shot this endangered species (member of a group of organisms in danger of dying out) as it was charging at them.

INSIDE AND OUT

Stroud begins the necropsy by placing the wolf on an examining table. Then, he uses a knife to remove its gray fur. He finds a clue: "There is a small bullet wound in the front of the wolf's neck," says Stroud.

Rather than dig around inside the animal for the tiny bullet, Stroud performs an X-ray. These high-energy waves reveal minuscule lead flakes scattered around the wolf's spine, a sign of bullet trauma. "When a bullet enters a body and hits bone, the bullet breaks apart," says Stroud. But no bullet showed up on the X-ray.

Stroud speculates that the bullet must have entered the wolf, partly broken apart, and then exited the animal's body. To test his hunch, Stroud threads a wooden dowel through the small opening on the wolf's neck, pushing it in until it pops out of another hole at the back of the neck. That hole's size and shape indicate it's an entrance wound.

Verdict? "The bullet entered in the back and exited at the front of the neck. This fact proves that the wolf was running away when shot," explains Stroud. One case is solved, but another mystery awaits scientists in the forensics wing.

GORY GUTS

Sometimes, scientists at the forensics laboratory aren't so lucky as to receive a whole animal carcass. Jim LeMay, a geneticist at the lab, recalls receiving a box from a state trooper that contained animal guts.

The story behind the guts? In August 2002, Rick Swanson, an Alaska state trooper, received a call about a possible moose shooting. The inform ant described seeing a hunter, and two moose lying on the ground nearby. The trooper headed out to investigate. "I went to the area, and I found a large gut pile [where the moose bodies had been sighted]," Swanson explains. For evidence, Swanson sealed in plastic bags some blood and tissue samples.

Luckily, the informant was able to identify the hunter. So Swanson went to the suspect's home with a search warrant to look for more evidence. Under a large tarp in the backyard, he found a moose hide and animal guts.

MATCHING MOOSE

Although the evidence was falling into place, Swanson hadn't cracked the case yet. He still needed to match the remains that he had found at the crime scene with those retrieved in the suspect's yard. To do this, he sent the collected samples to LeMay at the forensics laboratory.

LeMay uses DNA profiling (see Nuts & Bolts, right) to examine the samples. "For moose, I analyze 11 different markers (small chains of genes) along the DNA molecule," says LeMay. If those DNA sites match up between two samples, then those samples must be from the same moose. His finding: The samples from the crime scene match those from the suspect's home.

With foolproof evidence pointing to the suspect, police charged the shooter with illegally killing the two moose out of hunting season.

CRIME STOPPERS

As for the grizzly spotted by hikers in Katmai, the saga continues. When park service rangers reached the kill site, they spotted three more dead brown bears, including a cub. They sent the carcasses to the wildlife forensics lab for analysis.

What's next? With a little luck and a lot of expertise, the lab will analyze the new evidence from the bear case--and any other as-yet-unsolved mysteries--to help authorities catch wildlife criminals and deter more animal casualties.

Nuts & Bolts

DNA is a chemical that carries hereditary information. Shaped like a twisted ladder, a DNA molecule contains four nitrogen bases that pair up to create the ladder's "rungs." Adenine (A) binds with thymine (T), and guanine (G) pairs with cytosine (C).

In DNA profiling, scientists analyze specific regions of the DNA molecule from two or more samples. Because certain sections of DNA are unique to each person or animal, scientists can figure out if different samples come from the same individual.

CHECK FOR UNDERSTANDING

DIRECTIONS: On a separate sheet of paper, use details from the article to help you write the following:

1. You're a park ranger at a U.S. national park, and you're leading visitors on a nature walk. Explain to them why it's important to keep poachers out of the park.

2. You are a pathologist at the National Fish and Wildlife Forensics Laboratory. A state trooper just sent you a moose's severed hind leg, which contains a bullet wound. The trooper also said that an eyewitness reported seeing someone shooting the moose and then fleeing the crime scene with the rest of the animal's body. Explain the steps you would take to track down the culprit.

ANSWERS

Answers will vary, but they should contain the following points:

1. Nabbing poachers is critical to protecting wildlife Globally, the illegal sale of wild animals and their body parts--from bear hides to elephant tusks--yields about $5 billion a year Even though many of these wild animal species are protected under the Endangered Species Act. because of their value, some people would take risks to illegally kill a protected animal The result is a further dwindling of already endangered and threatened species

2. You begin with a necropsy to search for clues. Then, you take an X-ray image of the moose's severed hind leg to look for a bullet, which helps you determine how the animal was killed. Based on the eyewitness's description of the hunter, the trooper goes to the suspect's home. There, the trooper finds moose parts and then sends them to you. You use DNA profiling to examine the samples, analyzing 11 different markers along the DNA molecule. If the DNA of the moose found in the suspect's home matches that of the leg in the lab, you can positively conclude that the hunter shot the moose.