Skip to main content

How ‘Discarded DNA’ Helped Cops Legally Catch the Suspected Golden State Killer


Joseph James DeAngelo Golden State Killer mugshot arrest

At a live press conference Wednesday afternoon, authorities revealed how they caught the suspected “Golden State Killer.” They said “discarded DNA” led them to the man they believe committed twelve murders, 51 rapes, and 120 burglaries. The authorities didn’t go into many details, but they did admit the suspect had been placed under surveillance and that officers learned his routines. The authorities also said it was “dogged determination by detectives” which led them to the sample and, henceforth, to the suspect. Despite plenty of questions from local reporters about this “discarded DNA,” the authorities wouldn’t go into further details.

Other legal cases allow us to fill in the blanks as to how investigators probably did their work. The suspect, Joseph James DeAngelo, at some point apparently left his DNA behind at some location where officers were presumably watching him. Perhaps the suspect discarded a straw, or a cigarette butt, or some other piece of garbage. Whatever it was, something was discarded, and it contained DeAngelo’s DNA. The police took it and tested it, most likely without a warrant. What they tested apparently matched what the killer left behind at a crime scene. The crime scene evidence had apparently been preserved, probably in a cold storage locker in a crime lab, since at least some of original crimes between 1974 and 1986. That’s what “discarded DNA” is.

Many, including Bruce Harrington, whose brother and sister-in-law were the killer’s victims, said it takes far too long for DNA testing to be done in many cases, despite the crime scene evidence being in the possession of law enforcement.

The Fourth Amendment to the U.S. Constitution protects individuals against the unreasonable search and seizure of their houses, papers, persons, or effects. A search without a warrant is generally considered unreasonable and therefore unconstitutional; however, exceptions to that rule do apply. In California v. Greenwood (1988), the Supreme Court of the United States ruled that there is no constitutionally-protected privacy right to discarded items. That case specifically involved trash left for pickup beyond the constitutionally-protected “curtilage” of a house or home. In Raynor v. Maryland (2015), the Supreme Court refused to consider specifically whether DNA inadvertently shed by a defendant sitting in a police interview chair should be subject to a different constitutional analysis. In that case, a suspect in a 2006 rape case agreed to a police interview. When police asked the suspect for his DNA, he refused. As the state court pointed out:

Minutes after the interview concluded and [the suspect] had departed the station, the police, who had noticed [the suspect] rubbing his bare arms against the armrests of the chair in which he had been seated, took swabs of the armrests in an attempt to collect his DNA. The police submitted those swabs to the crime lab for DNA analysis, which revealed that the DNA extracted from the swabs matched DNA samples investigators had collected from the scene of the rape.

The issue the court examined wasn’t the collection of the DNA, but the subsequent testing of the DNA. The Maryland court ruled that the testing was legal:

[W]e hold that DNA testing of the 13 identifying junk loci within genetic material, not obtained by means of a physical intrusion into the person’s body, is no more a search for purposes of the Fourth Amendment, than is the testing of fingerprints, or the observation of any other identifying feature revealed to the public — visage, apparent age, body type, skin color.

Since the U.S. Supreme Court refused to take the case, the lower court’s decision stands. It’s persuasive, but not binding, in other states.

We don’t know exactly how the authorities got the suspect’s DNA in the Golden State Killer case, but these cases are telling as to how they probably did it.


[Image via the Sacramento, California Sheriff’s Office.]

Have a tip we should know? [email protected]

Filed Under:

Follow Law&Crime:

Aaron Keller holds a juris doctor degree from the University of New Hampshire School of Law and a broadcast journalism degree from Syracuse University. He is a former anchor and executive producer for the Law&Crime Network and is now deputy editor-in-chief for the Law&Crime website. DISCLAIMER:  This website is for general informational purposes only. You should not rely on it for legal advice. Reading this site or interacting with the author via this site does not create an attorney-client relationship. This website is not a substitute for the advice of an attorney. Speak to a competent lawyer in your jurisdiction for legal advice and representation relevant to your situation.