The trial of OJ Simpson, 20 years later

LOS ANGELES – The OJ Simpson murder trial shone a harsh light on the work of police and forensics and provided law enforcement with a textbook example of what not to do at a crime scene.

At the trial two decades ago, Simpson's defense attorneys clearly demonstrated the prosecution's argument by exposing the Los Angeles Police Department's problems with evidence handling. Some of the lessons: follow procedures, make sure evidence is always considered and properly recorded, and be brutally honest with the jury, even when it hurts.

“If your job is to clean the streets of bad people … and you can't successfully prosecute them because you're incompetent and can't do your job, then you've failed in your primary mission,” says Mike Williamson, a lawyer and former LAPD officer.

After Simpson was acquitted of killing his ex-wife Nicole Brown Simpson and her friend Ronald Goldman, the LAPD made significant changes to its Scientific Investigation Division, which defense attorney Johnnie Cochran called “a cesspool of contamination” because of sloppy evidence.

As a result of these headlines, the crime lab received more funding and additional staff and was accredited in 1997.

“One of our most important lessons from the Simpson trial was the interview. It was difficult to prove from our notes that work was done in a particular way,” said Doreen Hudson, who now heads the crime lab.

Analysts began taking more detailed notes so that information was retained rather than remembered.

Henry Lee, the defense's forensic expert during the trial, said that while there was a large amount of evidence, the source of the evidence was not always explained and the evidence was not closely followed.

During the case, no one noticed blood on a pair of socks taken from Simpson's bedroom until two months later at the crime lab. Defense experts theorized that the blood was smeared on the socks when they were lying flat, not while someone was wearing them.

The defense also accused police forensic scientists of improperly packing evidence and leaving it in an overheated van on a summer day. An inexperienced technician had collected most of the evidence.

The lab now uses barcodes to scan and track evidence. And crime scenes are also more tightly controlled. Trainees like the one who helped at several crime scenes in the Simpson case can now only observe the work of two fully trained criminalists.

“We are more aware of contamination or the possibility of contamination or the appearance of contamination – that a jury could throw out some evidence,” said Commander Andrew Smith.

Under the supervision of a crime scene manager who coordinates with detectives, crime teams now respond to spectacular and complex crimes, Hudson says.

Another point of criticism during the trial concerned a vial of blood taken from Simpson. Police Detective Philip Vannatter had drawn blood from Simpson at the LAPD on June 13, the day after the murders. But instead of registering it as evidence, Vannatter put the vial in his pocket and went to Simpson's house, where detectives were collecting evidence.

Jurors questioned why he carried the gun for hours instead of registering it, and the defense argued it could have potentially been used to plant evidence, such as drops of blood, on Simpson's sidewalk.

Today, that would no longer happen, says Hudson. Police officers are still distracted when they follow a suspect or victim to a hospital, for example, before returning to the crime scene. But today, they are no longer allowed to re-enter a crime scene with evidence.

Looking back on the case, Hudson said, “The only thing you can do when something really bad happens is try to make something good out of it.”