Forensic Science Is Often Used to Solve Crimes

I'm Steve Ember.  And I'm Faith Lapidus with Explorations in VOA Special English. Today we tell about forensics – a special kind of medical science used to solve crimes.

From nineteen seventy-six to nineteen eighty-three, a military dictatorship in Argentina carried out a campaign to kidnap, torture and kill its critics. About twenty thousand men, women and children were lost in Argentina's so-called "dirty war."  The victims were never found and became known as the "disappeared."

The military government fell in nineteen eighty-three.  The new civilian government invited forensic scientists from the United States to investigate the killings.  Anthropologist Clyde Snow and a group of Argentinean university students discovered remains in hundreds of mass graves. The bones they collected helped prove the mass killings. In nineteen eighty-five, six of nine former Argentine military leaders were found guilty for the deaths of the "disappeared."

Clyde Snow and the Argentinean students used archeological techniques and laboratory methods to identify the "disappeared."  Clyde Snow says such forensic investigations are done for three reasons.

CLYDE SNOW: "The first is to collect the forensic evidence in the hopes that eventually some justice can serve the needs, such as we did in the junta trial in Argentina."

Mr. Snow says the second reason is to establish a historical record that can be used in a court of law.  And a third reason for forensic investigations is to return any remains of victims to their families.

Today, the work of forensic investigators has captured the public's imagination. Several popular television shows, films and best-selling books have led to a new form of entertainment. In most situations, forensic investigators solve violent crimes.

How does forensic medicine establish facts about something that is unexplained? How does it provide evidence that can be used against people guilty of violent crimes?  The answer is based on years of work by experts.

French anthropologist Alphonse Bertillon created the first record-keeping system of criminals in eighteen seventy-nine in Paris.  It included physical measurements and photographs of individual criminals. French police used the descriptive information to identify suspects.

In eighteen eighty-four, Mr. Bertillon used his system to help French police identify more than two hundred repeat criminals.  Police in Europe and the Americas used the system as well.  In time, law enforcement moved away from this system to fingerprint identification.  Yet, parts of the system are still used today.  These include the traditional "mug shot" or photograph of the suspected criminal after he or she is arrested.

In the second half of the nineteenth century, forensic science became interested in other ways to identify criminals.  In Argentina, police official Juan Vucetich developed the first workable system of fingerprint identification. In eighteen ninety-two, he was also the first person to successfully use fingerprint evidence in a murder investigation. The case involved the murder of two boys in a village near Buenos Aires.

Police suspected a man linked to the boys' mother.  But the police could not get their suspect to admit to the crime.

Investigators found a bloody fingerprint while studying the crime area.  Mr. Vucetich compared the fingerprint to those of the male suspect and the boys' mother. The fingerprint matched one of the mother's.  When presented with the evidence, she admitted her guilt.

In the nineteenth century, low-cost manufactured chemicals began to be used in homes, farms and industry.  Many of these chemicals were poisonous to humans.  Poisoning became a method of killing that was sometimes hard to identify.  So researchers developed toxicology as a kind of forensic medicine to help solve crimes.

Toxicologists identify small amounts of poisons and other substances through a series of tests. Such tests might involve blood, bodily fluids, tissue or a piece of hair examined under a microscope. In fact, scientists can establish a person's complete history of drug use by studying one small piece of hair.

British chemist James Marsh developed the most famous toxicology test in eighteen thirty-six. The Marsh Test is used to identify small amounts of arsenic poison.  Mathieu Joseph Bonaventure Orfila used the test in eighteen forty to help solve a disputed murder case in France.  Mr. Orfila is considered the "father of toxicology."  He worked to make the study of chemicals a common part of forensic medicine.

Today, researchers continue to discover new ways to separate, study and identify chemical substances in the body.  One of the more modern technologies is gas chromatography, which separates substances.  Another modern technology is mass spectrometry. This method measures the mass of molecules.  Both help toxicologists identify very small amounts of poison in the bodies of victims. The technologies also help investigators collect evidence after a crime.

Forensic radiology is another modern method used by investigators to solve crimes.  Radiology can make images of what is hidden in the body.  Forensic radiologists use X-rays, computer tomography and magnetic resonance imaging to follow the path of objects inside the body.  Radiologists can use this technology to identify the remains of bodies destroyed beyond recognition.

A forensic odontologist uses radiology to examine evidence related to teeth. Such technology helped solve a horrible crime in two thousand three in Switzerland. Three women were found beaten to death in a building near Zurich. One of the victims had a bite mark on her shoulder. Scientists created models of teeth and used radiological images to prove the guilt of a suspect.

Today, new technologies are changing forensic science. For example, investigators increasingly use genetic tests involving D.N.A. to identify people, including criminals.  Every cell in every living thing contains D.N.A., the molecule that carries genetic information. 

In nineteen ninety-eight, D.N.A. tests helped identify an American soldier buried in the Tomb of the Unknowns in Arlington National Cemetery in Virginia. First Lieutenant Michael Blassie had been shot down over South Vietnam in nineteen seventy-two. Almost twenty years later, his family received word that his remains might be buried in the cemetery near Washington, D.C.

The family urged the Department of Defense to open the Tomb of the Unknowns and carry out D.N.A. tests on the damaged bones inside.  A match was found and the remains of First Lieutenant Blassie were returned to his family in the state of Missouri.

D.N.A. tests have been used to study blood and other bodily fluids to identify suspects of crimes. These tests have also shown that some people found guilty of crimes were really innocent. For example, in nineteen eighty-five, Kirk Bloodsworth was sentenced to death for the sexual torture and murder of a nine-year-old girl.  A Maryland court found him guilty based on information from an unidentified person and reports that placed him near the crime area. No physical evidence had linked him to the killing.

In prison, Bloodsworth learned about D.N.A. testing.  With the help of his lawyer, he urged officials to compare his D.N.A. with evidence from the trial. The tests proved his innocence.  Kirk Bloodsworth won his freedom in nineteen ninety-three.

A nonprofit legal organization called The Innocence Project supported the case. The group is based in New York City.  It was created to support the use of D.N.A. tests to help release innocent prisoners. The Project says more than one hundred seventy-five prisoners have been found innocent of their crimes because of D.N.A. testing.

The use of forensic science to identify and punish violators of human rights has spread around the world.  In two thousand five, there were forensic human rights investigations in more than thirty countries. Investigators have documented victims of mass murders as well as those responsible for the crimes. Anthropologist Clyde Snow says the "disappeared" in Argentina started the movement.

CLYDE SNOW: "Our work in Argentina was the first in which the forensic sciences were used in the investigation of human rights abuses."

But experts say forensic teams work at great personal risk in countries where human rights violators remain in power.

This program was written and produced by Jill Moss. Our audio engineer was Wojciech Zorniak.  I'm Faith Lapidus. And I'm Steve Ember.  Join us again next week for Explorations in VOA Special English.