Simpson Case DNA Battle Will Be an Education for Many

For both the media and the public, the most difficult part of the O.J. Simpson trial is now beginning--the battle over DNA and whether it links the defendant to the murder of his former wife Nicole Brown Simpson and her friend Ronald Lyle Goldman.

We are not the only ones who will have trouble fathoming the intricacies of DNA, the abbreviation for a molecule called deoxyribonucleic acid. It is a skinny molecule that contains the genetic information determining eye color, blood type and all the other features that make each individual unique. It is the understanding of DNA that has made possible research into genetic defects and many of the other great scientific advances of the past several years.

The police, too, have had difficulty in dealing with DNA evidence. The old homicide detectives operated on gut instinct. They could sense the killer, and nail him with a few clues and hours of rough questioning. Catching a killer with DNA evidence requires different skills.

Like most police departments, the LAPD has been working with DNA for several years and has faith in its ability to do so. But last week, the Simpson defense team took aim at that ability, trying to portray the L.A. detectives as old-line cops who rely on their instincts and who are uncomfortable with the stringent and demanding process required for gathering blood and reading the DNA.

That is why the defense, in tedious detail, forced the cops to describe each of their steps at Nicole Simpson’s Bundy Drive condo. The Simpson team’s aim is to show that the LAPD, unskilled with this brand of forensic science, traipsed clumsily through the crime scene, polluting it so badly that the most important evidence--blood containing the DNA of the victims and the killer--was contaminated.

The prosecution, of course, will contend that the cops are on the cutting edge of the science. But to do this, the D.A.’s office will have to do a real selling job.

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This new forensic science involving DNA was not used in a criminal case until 1986, in England, and not in the United States until a year later. Today’s veteran cops were well into their careers when DNA evidence began emerging in criminal cases.

Thus police have had to tackle a very complex science that many of them were not prepared for. I got a sense of this process of education from a book to be published in the late spring, “Stalking Justice,” by Santa Monica attorney Paul Mones. It is the story of an experienced detective who, when instinct couldn’t do the job, used DNA to catch a serial killer. The convicted man, Timothy Spencer, became the first person in the United States to be executed as the result of DNA evidence.

The detective in the book, Joe Horgas of the Arlington County, Va., Police Department, didn’t have much patience for painstaking examination of a crime scene and careful collection of evidence.

“I never was a crime scene agent like a lot of guys on the squad, so I don’t really have an intense interest on how they collect evidence,” Horgas told author Mones.

But his instinct carried him only so far in the hunt for a serial rapist-killer at large in the suburban community across the Potomac from Washington, D.C. Two days before Christmas, 1987, Horgas looked at a brochure on Lifecodes, a laboratory in New York state that did DNA testing. A few days later he brought to the laboratory 15 blood and semen samples.

Like many people, Horgas had a vague idea of DNA from long-ago high school biology. But the people at the lab had to give him a science lesson.

Mones’ book describes that lesson, going into how scientists treat the blood or semen with a chemical that separates out the DNA. The microscopic strands of DNA look like long twisted ropes. The strands are then cut into pieces. From these pieces scientists determine the pattern of an individual’s DNA. They do this by placing the DNA on a sheet of film. On the film, the segment of DNA looks a bit like a supermarket pricing bar code. If the suspect’s bar code matches that on the DNA extracted from the crime scene, it’s probable that the cops have the right person.

Detective Horgas, meanwhile, remembered a young burglary suspect, Timothy Spencer, from a decade ago. There was something about his methods that reminded Horgas of the rapist. The hunch led to Spencer’s arrest, but the cops had no real reason to hold him. Spencer agreed to a blood test, and Horgas sent the sample to Lifecodes. A few weeks later, the lab reported that the segment of Spencer’s DNA matched those taken from the bodies of several of the victims, and from bathrobes, pants, nightgowns, sanitary napkins and blue jeans at the crime scenes.

Joe Horgas, who once didn’t want to know the details of evidence collection, became a believer in the new forensic science.

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Getting the conviction in the Spencer case would not have been so easy today. The defense has learned to contest the validity of DNA. Some of the foremost DNA experts in the country are now working on the defense side in criminal cases.

What this means is you can expect a battle over each of the samples submitted as evidence, and over the manner in which they were collected. Last week, for example, the prosecution announced that bits of dried blood had been found on the rear gate of Nicole Simpson’s condominium and that the DNA extracted from it matched Simpson’s. Expect the defense to say the sample has been contaminated, or could have belonged to one of the Simpson children.

The arguments over these samples and the others will be hard to follow. Most of us are like Detective Joe Horgas. We either didn’t learn about DNA in school, or if we did, we forgot most of it.

Stick with it. When this trial is completed you’ll have had a scientific education. And you will have seen one of the most important fights over DNA in the history of criminal law.