How DNA Changed the Course of the Green River Killer Investigation

For nearly two decades, shoe prints, lie detector tests, bodily fluid samples and even a criminal profile created by none other than serial killer Ted Bundy, were useless in the search for the infamous Green River Killer. This was until 2001, when the advancement of brand new method of analysis – which was previously regarded with skepticism and treated with doubt – was applied. Laymen and experts alike had previously questioned its usefulness in identifying a suspect.

The consolidation of DNA fingerprinting was a game-changer in forensic science. In fact, we’ve already covered five times DNA profiling changed everything in another article.

Read on to find how how nearly twenty year-old DNA changed the course of the Green River Killer investigation and finally brought it to its conclusion.

You better watch your back: the killing spree

The Green River Killer started his killing in 1982 – this much we know – however, it is challenging to determine exactly who met her fate first at this killer’s hands.

While travelling down the Green River in his rubber raft, Robert Ainsworth floated upon the lifeless body of a woman. Mere seconds later he noticed the body of a second woman drifting nearby. Investigation of the scene by law enforcement revealed a third macabre finding: the body of yet another young girl hidden in the grassy area on the riverbank.

The grisly trio were not the first discoveries — just days earlier, a woman’s body was discovered slumped over a log in the Green River, and a month before that another female’s body was found floating in the river. Six months prior, her friend was discovered in a parking lot a few miles from this scene. All had been strangled.

In fact, murder by strangulation was just one of the things the killer’s suspected ninety victims had in common. Another primary similarity was that they all, for the most part, had a history of prostitution or were runaways. He would usually engage in sexual intercourse with them before strangling them to death and subsequently dumping their body in the wooded area around the Green River.


Too close for comfort: a suspect

The police were stumped and, even though the rate of murders had decreased, finding the killer was still on a top priority. A breakthrough came in 1987 when police obtained a search warrant for a suspect’s house — a suspect that had been on the police’s radar for some time.

The suspect was Gary Ridgway who had initially been accused of choking a prostitute in 1980 — does this sound familiar? He was released after pleading self-defence after she bit him. On several other occasions, Ridgway had gained police attention due to his penchant for prostitutes. After one such incident, when he attempted to pick up a police officer who was undercover, he even took a lie detector test. He passed and was freed.

Further suspicion arose when police discovered that Ridgway frequented the dumpsites where many of the victims had been found and, perhaps in the most incriminatory move of all, was absent from work every time a victim went missing.

Finally, in 1987 along with the search warrant, police were able to obtain samples of bodily fluid from the suspect to match to the Green River victims. Unfortunately, there was insufficient evidence and Ridgway was free once more.

The main investigator leading the case died shortly after and after a series of false leads, media accusations and dead ends. The case lay somewhat dormant for ten years.


The big break: DNA to the rescue

In 2001, Detective Reichert, the new sheriff of King County, restarted investigations into the murders. He was driven by a determination to catch the monster behind the nearly fifty known deaths. Unlike in the initial investigations, the police now had cutting-edge technology on their side.

One such technology was DNA analysis, a discipline that had undergone rapid advancement since the first murders. The development of the polymerase chain reaction (PCR) test and the short tandem repeat (STR) test allowed scientists to analyse minute samples of DNA. STR analysis allows short repeat units to be extracted before PCR testing which amplifies the amount of DNA present by creating thousands to millions of copies of a single strand.

The first samples to be sent to the lab were found on three victims that were murdered between 1982 and 1983. The samples consisted of semen supposedly belonging to the killer. These samples were compared to those taken from Ridgeway all the way back in 1987 and on the 10th of September 1987, the police finally got what they had been seeking for twenty years: the Green River Killer’s identity.

While Gary Ridgway was “only” charged with the murders of forty-nine women, he admitted to killing seventy-one. The true number of victims is thought to exceed ninety. Ridgway even once said that he had killed so many it was hard to keep count. He is currently imprisoned at Washington State Penitentiary, having escaped the death penalty in exchange for helping police to locate the other victims and providing other details.

Your turn: Do you think that other cold cases should be reinvestigated using DNA analysis where possible? Leave us a comment down below — we’d love to hear your thoughts.



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