How 'Golden State Killer' Was Unveiled

choi

In chronological order. (I am interested in technological aspects of identification of the suspect. There is no need to read the rest; If you must, read only (2)(b).)

(1) Thomas Fuller, Genealogy Site Led to the Suspect's Front Door. New York Times, Apr 27, 2018, at page A19.
https://www.nytimes.com/2018/04/26/us/golden-state-killer.html

Quote:

"The Golden State Killer raped and murdered victims across California * * * The suspect, Joseph James DeAngelo, 72, was arrested by the police on Tuesday. [He was implicated in] more than 50 rapes and 12 murders [and over 100 burglaries 1974 through 1986: en.wikipedia.org]

Through DNA: " 'We found a person that was the right age [and sex: it has to be male] and lived in this area — and that was Mr DeAngelo,' said Steve Grippi, the assistant chief in the Sacramento district attorney's office.  Investigators then obtained what Anne Marie Schubert, the Sacramento district attorney, called 'abandoned' DNA samples from Mr. DeAngelo. 'You leave your DNA in a place that is a public domain,' she said.  The test result[s were] * * * matching the full [100%] DNA profile [with Mr DeAngelo].

"The big players in commercial DNA testing — including 23andMe and AncestryDNA — extract genetic profiles from the saliva that customers send to the company in a tube by mail. It would not be easy for law enforcement to upload a profile to one of those sites. Over the past few years, numerous smaller genealogical websites have emerged, however, giving customers more avenues to upload a DNA profile and search for relatives. * * * [One of those sites] GEDmatch said in its statement that it had warned those who used its site that the genetic information could be used for other purposes. 'If you are concerned about non-geneatological uses of your DNA, you should not upload your DNA to the database and/or you should remove DNA that has already been uploaded,' the statement said.

"The Golden State Killer, also known as the East Area Rapist, tormented his victims with sadistic rituals. Some he shot and killed with a firearm. Others were bludgeoned to death with whatever he could find — in one case a piece of firewood. He had many trademarks: He wore a mask, he bound his victims’ hands. He started by raping single women and then went on to raping married women with their husbands present, before killing them both.

"Eighteen years ago she [Ms Schubert, the DA] reached out to an investigator [David Holes; see (2)(b)] from Contra Costa County who specialized in the East Area Rapist, beginning a collaboration to re-energize the case.

My comment:
(a) Mr DeAngelo is a former police officer in Auburn [a city in Placer County] and Exeter [a city in Tulare County], California.

The Placer County is on the northern border of Sacramento County, California. Tulare County is quite far from Sacramento County.
(b) Newspapers today (Apr 28) does not elaborate on "abandoned DNA" broached in quotation 1. I imagine that at the behest of investigators, an old colleague of Mr DeAngelo invited him for a dinner, and Mr DeAngelo drank from a cup. Bingo.

choi

(2)
(a) Gina Kolata and Heather Murphy, Stores of DNA That Anybody Can Pore Over; Privacy worries in case of Golden State Killer. New York Times, Apr 28, 2018(front page: 1 of 2 top reports).
https://www.nytimes.com/2018/04/ ... ller-genealogy.html

Quote:

"In the years since [Mr DeAngelo last struck in 1986], scientists have developed powerful tools to identify people by tiny variations in their DNA, as individual as fingerprints.

Investigators "recently found an unusually well-preserved sample from one of the crime scenes [see (2)(b)]. The problem was finding a match. * * * a near-match ultimately was found in a genealogy website beloved by hobbyists called GEDmatch, created by two volunteers in 2011.  Anyone can set up a free profile on GEDmatch. Many customers upload to the site DNA profiles they have already generated on larger commercial sites like 23andMe [and Ancestry.com].  The detectives in the Golden State Killer case uploaded the suspect’s DNA sample. But they would have had to check a box online certifying that the DNA was their own or belonged to someone for whom they were legal guardians, or that they had 'obtained authorization' to upload the sample. [And investigators lie to join. But so what? There is no liability or crime for such falsehood.]

"The matches found in GEDmatch were to relatives of the suspect, not the suspect himself.  Since the site provides family trees, detectives also were able to look for relatives who might not have uploaded genetic data to the site themselves.

"23andMe has more than 5 million customers, and Ancestry.com has 10 million.

My comment: About quotation 1. A rape suspect in Boston claimed innocence, insisting that it was his identical twin, not he. Massachusetts finally got the break through advance in DNA. because twins share identical DNA at the stage of an fertilized egg, they diverse little by little with time, owing to random mutations here and there (referring to different cells of the body, as well as different locals of DNA).

(b) Tim Arango, Adan Goldman and Thomas Fuller, With Fake Genealogy Profile, Detectives Hunted for a Killer; After two decades of searching, an online breakthrough. New York Times, Apr 28, 2018, at page A17.
https://www.nytimes.com/2018/04/ ... oseph-deangelo.html

Quote:

"SACRAMENTO — To solve a decades-old serial rape and murder case that had gone cold, investigators used DNA gathered at a crime scene and created a fake profile and pseudonym on a genealogy website several months ago, according to law enforcement officials.

"GEDmatch, the genealogy site, confirmed in a statement on Friday that law enforcement officials had used its database. The FBI declined to comment.

"On Friday [Apr 27] Mr DeAngelo made his first court appearance since he was arrested.  He was wheeled into a prison courtroom in Sacramento wearing an orange jumpsuit * * * Diane Howard, a public defender who has been appointed his legal counsel * * * 'I'm privileged to be able to represent him,' she [Howard] told reporters in the foyer of the Sacramento County Main Jail. 'That's what we do.'

"It took about four months, from when the first possible links appeared on GEDmatch to when Mr DeAngelo was arrested. Mr [David] Holes contrasted that time frame with the decades of shoe-leather police work [he had been 'working the case for 24 years': quoting this report] that had always come up empty. 'It underscores the power of this technology,' he said.

"After a meeting in March 2017 of investigators in the case, Mr Holes focused his efforts on genealogy * * * there was still one problem: Many of the known DNA samples of the suspect had degraded over the years.  Eventually, Mr Holes learned of a never-touched DNA sample from a 37-year-old murder in Ventura County that was sitting in a freezer. The medical examiner in Ventura at the time, Claus P Speth, made a habit of producing duplicate rape kits, one for the investigation and one stored for later, just in case.

"It is unknown if investigators used more than one genealogy site [I bet they did, but were unsuccessful].

"Mr DeAngelo will not be charged for a series of rapes authorities believe he committed in the Sacramento area in the late 1970s because the statute of limitations has expired, Sheriff Scott Jones of Sacramento County said in an interview on Friday.

Note: About "shoe-leather police work" in quotation 2.
(a) shoe-leather (adj): "involving or using basic, direct, or old-fashioned methods  <shoe-leather journalism>"
https://www.merriam-webster.com/dictionary/shoe-leather
(b)
(i) For etymology, see
Denise Koo and Stephen B Thacker, In Snow's Footsteps: Commentary on Shoe-Leather and Applied Epidemiology. American Journal of Epidemiology, 172: 737–739 (2010).
https://academic.oup.com/aje/article/172/6/737/99608
(shoe-leather epidemiology)
(ii) John Snow
https://en.wikipedia.org/wiki/John_Snow
(photo)