Mr. Wizard Comes to Court

By Bennett H. Beach

New scientific evidence is helping to show jurors whodunit

Did Wayne Williams murder Nathaniel Cater and Jimmy Ray Payne? No one saw either crime, and there were no fingerprints. But there is plenty of circumstantial evidence in the extraordinary Atlanta case, including carpet fibers found on the victims and bloodstains in Williams' station wagon. So prosecutors are placing their faith in test tubes, microscopes and forensic specialists; in hour upon hour of testimony, experts have said that all the scientific evidence points to Williams. Last week the defense fought back. Kansas State University Professor Randall Bresee claimed that the prosecution's fiber analysis was too imprecise. In fact, said Bresee, he had examined fibers from a carpet in Defense Attorney Mary Welcome's office and found them "microscopically similar" to those from Williams' home.

No matter who prevails, the trial is highlighting a major development in the criminal courtroom. With the help of a variety of technical advances, more and more silent evidence is being turned into loudly damning testimony. FBI Laboratory Chief Thomas Kelleher (whose technicians handle half a million pieces of evidence a year) reports that forensic science is growing so fast that even the most sophisticated researchers cannot keep up. The granddaddy of scientific evidence is the fingerprint, introduced in 1901. Because a person's print is unique, there is still no better physical evidence. But now there are a number of new ways of Unking a criminal to a crime that are nearly as clear-cut. Suspects are being asked not only for fingerprints but for footprints, blood samples and pieces of hair.

Over the past ten years, no area has developed faster than the examination of bloodstains. "Before, we used to be satisfied with identifying a blood sample as type A, B, AB or O. Now we have 13 or more different antigen and enzyme systems we can pick out," says Gary Howell, 34, director of the Kansas City regional crime lab. The probability that any two people will share the same assortment of these blood variables is .1% or less. Because of that, Howell was recently able to use two tiny bloodstains to help convict a double murderer.

Another use of blood is also winning wide acceptance. Scrutiny of the size, shape and distribution of blood spatters tells much about the location and position of a person Involved in a crime and thus may dispute a defendant's version of what happened. Blood that travels at an angle, for example, leaves an elliptical stain. Consultant Herbert Leon MacDonell, 53, of Corning, N.Y., the leading expert, is now sought out in more than 100 homicide cases a year. At the trial of Jean Harris last year he tried to persuade the jury--unsuccessfully--that blood marks jibed with Harris' claim that the shooting of Dr. Herman Tarnower occurred accidentally during a struggle.

Another famous trial, that of Theodore Bundy, has greatly helped to increase the use of bite-mark evidence. Bundy was convicted in 1979 of murdering two sorority sisters after photographs of bites found on one of them were matched with impressions taken of Bundy's teeth. Since then, the use of bite evidence has "skyrocketed," says Miami Dentist Richard Souviron, a frequent witness--not only in sex-murder cases but child-abuse investigations as well.

Even anthropology is making a courtroom contribution. University of North Carolina Anthropologist Louise Robbins applies the same procedures used on prehistoric footprints to modern mysteries. "There are 46 points of measurement and 120 points to examine for shape," she says. "I have not yet found even so-called identical twins with absolutely identical foot prints." She can identify barefoot prints as well as match a shoe to its wearer. Says Robbins: "If you'll check your shoes, you can see the marks for your toes."

Police are also obtaining information from tire tracks left at the crime site. The man they most often call is Peter McDonald, a veteran designer of tires with Firestone. He can identify almost any tire made and, with the added distinctive details provided by the individual way a tire tread wears down, McDonald has helped solve six murders. In one case, McDonald was first able to show that the car of a suspect in custody did not have the right tires; he then helped nail the actual killers.

The use of scientific evidence has become so common, says Washington University Law Professor Edward Imwinkelried, that a prosecutor who has none to offer sometimes feels obliged to explain why. Such testimony is particularly critical in rape cases for corroboration and in homicides, where there may be no eyewitnesses. One danger, though: it can become so complicated that the jury gets lost. That is often the only hope for defense attorneys, who can rarely afford to hire opposing experts. In cross-examination and final arguments, they hammer away at the witness's credentials or the inability to pin the crime on the defendant conclusively.

Scientific advances do not always perform as promised. The reliability of some supposed wonders, including lie detectors, voice-print machines and hypnosis, are so in doubt that many courts will not hear the resulting evidence. But more, not less, scientific evidence is likely in the future. With the help of an ion chromatograph, FBI technicians are starting to determine not only the type but even the manufacturer of explosive substances. Lasers are enabling experts to lift fingerprints from difficult surfaces like cloth and even the human body. Kansas City's Howell believes that the coming years will see a great increase in the use of weapon marks. In one stabbing murder, researchers compared a section of the victim's trachea with cuts made in a bar of soap by the suspect's knife. Under a microscope, the marks matched, and the defendant pleaded guilty.

Hair is still another source of information. A single strand can reveal a person's sex, race and certain other characteristics, and experts now have the ability to read far more from a sample. Says New York City Forensic Serologist Dr. Robert Shaler: "The hair is the garbage can of the human body. Everything you eat shows up there." Knowing that it grows about 1 mm a day, Shaler insists, "we can tell if you took aspirin yesterday and drank beer from an aluminum can a week ago." Until now, only Sherlock Holmes could deduce so much from so little. --By Bennett H. Beach. Reported by Jay Branegan/Chicago and Marc Levinson/Atlanta

With reporting by Jay Branegan, Marc Levinson

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