Crime Library: Criminal Minds and Methods

Serology: It's in the Blood

Blood Trails, DNA and O.J.

Since 1985, with Alec Jeffrey's discovery of the uniqueness of portions of the DNA structure of certain genes, investigations involving blood have taken an entirely new turn. While the ultimate goal of the analysis of proteins and enzymes was to individualize blood, that's pretty much established with DNA technology. Within a year of the discovery, DNA typing was being put to the test in criminal cases. It not only cleared one man who had confessed to a crime, but also led to the conviction of the actual killer in the same crime.

O.J. Simpson
O.J. Simpson

DNA can narrow down suspects in a hurry, but it's not fool-proof. It can be challenged in court on the basis of sloppy evidence collection and the corruption of samples during testing. That was the tactic that O. J. Simpson's defense team used to win for him an acquittal in his double murder trial.  Just how did they manage to accomplish this? To trace their strategy, let's look at the case.

On the night of July 12, 1994, Nicole Brown Simpson and Ronald Goldman were slaughtered outside her Brentwood, California home. Nicole was the former wife of football celebrity O. J. Simpson, and he was called in from out of town for questioning. Going to his home on the night of the murder, detectives had noted a bloodstain on the door of his white Ford Bronco and a trail of blood leading up to the house. That was suspicious enough to start asking questions.

Nicole Brown-Simpson
Nicole Brown-Simpson

When Simpson returned to Los Angeles, investigators noticed a cut on a finger of his left hand. He told several conflicting stories about how he had gotten it, which boxed him in later when blood at the crime scene indicated that the killer had been cut on his left hand and had trailed blood outside the gates. That hardly seemed coincidental.

Then when several droplets of blood at the scene failed to show a match with either of the victim's blood types, Simpson's blood was drawn for testing (after the droplets had already been collected). Comparison between his DNA and that of the blood at the scene showed strong similarities. The tests indicated that the drops had three factors in common with Simpson's blood and only one person in 57 billion could produce an equivalent match. In addition, the blood was found near footprints made by a rare and expensive type of shoe — shoes that O. J. wore and that proved to be his size.

Ronald Goldman
Ronald Goldman

Next to the bodies was a bloodstained black leather glove that bore traces of fiber from Goldman's jeans. The glove's mate, stained with blood that matched Simpson's, was found on his property. There were also traces of the blood of both victims lifted from inside Simpson's car and house, along with blood that contained his DNA. In fact, his blood and Goldman's were found together on the car's console.

Forensic serologists at the California Department of Justice, along with a private contractor, did the DNA testing. Then other evidence emerged, such as the testimony of the limousine driver who came to pick Simpson up for the ride to the airport: On the night of the murder, while he waited for Simpson, he had seen a black man cross the driveway and go into the house. Then Simpson claimed that the driver had been unable to get him on the intercom because he had "overslept." So then who was the black man who had entered the house?

Barry Scheck
Barry Scheck

When arraigned, Simpson pleaded Not Guilty and hired a defense team of celebrity lawyers. Barry Scheck and Peter Neufeld from New York were the DNA experts, renowned for their work on the Innocence Project, which used DNA analysis to defend the falsely accused. Scheck felt confident that they could produce challenges before the jury that would both educate and persuade them.

The reliability of this evidence came to be called the "DNA Wars," and three different crime labs performed the analysis. All three determined that the DNA in the drops of blood at the scene matched Simpson's. It was a 1 in 170 million match, using one type of analysis known as RFLP, and 1 in 240 million match using the PCR test.

Peter Neufeld
Peter Neufeld

Nevertheless, criminologist Dr. Henry Lee testified that there appeared to be something wrong with the way the blood was packaged, leading the defense to propose that the multiple samples had been switched. They also claimed that the blood had been severely degraded by being stored in a lab truck, but the prosecution's DNA expert, Harlan Levy, said that the degradation would not have been sufficient to prevent accurate DNA analysis. He also pointed out that control samples were used that would have shown any such contamination, but Scheck suggested that the control samples had been mishandled by the lab — all five of them — and the jury bought it.

The evidence was damning, but the defense team managed to refocus the jury's attention on the corruption in the Los Angeles Police Department. They then disputed the good reputation of the forensics labs, insisting that the evidence had been carelessly handled. Deliberating less than four hours, the jury freed Simpson with a Not Guilty verdict. They simply failed to understand how damning the DNA evidence really was and how ill-fitting was the defense's logic about certain aspects of the blood at the crime scene.

Nevertheless, it can certainly be the case that what appears to be overwhelming blood analysis evidence still fails to tell the whole story. We can see that in the next case, a family tragedy that happened in Australia.

 

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