Home – How Deep Research Helped Identify a Serial Predator

How Deep Research Helped Identify a Serial Predator

Posted on 05-08-2018 by Korinne Bressler

Four decades after the notorious Golden State Killer’s crime wave ends, a 72-year-old suspect is wheeled into a Sacramento courtroom, thanks to an investigator’s unswerving determination over 24 years. While it may sound like a movie pitch—and perhaps it will hit the big screen someday—the story is real. Just a few weeks ago, Joseph James DeAngelo was arrested in a Sacramento suburb. How did the investigation move from mystery killer to DNA match? Research—and lots of it.

Systematic Approach to Research Yields Answers

According to a Washington Post article on the investigation, it began with a duplicate evidence kit from 1980 that the pathologist had fortunately frozen, avoiding the depletion of the sample’s value that other evidence had suffered over the years. The sample was fed into GEDmatch, a website that searches across one million genetic profiles to find family connections. GEDmatch uncovered 10 to 20 distant relatives linked to the Golden State Killer, but deeper research was needed. The Washington Post writes, “A daunting task lay ahead as Holes and his team began to trace offspring to the present day to find potential suspects. That meant filling in thousands of blanks.” 

The investigation looked back as far as the early 1800s to uncover the common denominator among the GEDmatch individuals—their great-great-great grandparents.  Once they narrowed down the shared ancestor, the painstaking work of building out the family trees to find a viable suspect began. “They used census data, old newspaper clippings and a gravesite locator to find the deceased relatives. When they got to the current day, they turned to police databases and websites such as LexisNexis,” reports the Washington Post.

Eventually, they had 25 extensive family trees, including one 1000-member tree that included the suspect. After narrowing the pool down further based on men who were the right age and lived in the right areas to fit the killer’s profile, they had uncovered two potential suspects. With a positive DNA match, the finger pointed squarely at a former police officer who likely used his knowledge about police procedure to stay one step ahead of investigators.

More Mysteries are Waiting to be Solved

Of course, deep research isn’t just for crime-solving. Investigative journalism has inspired Hollywood hits and award-winners—from 1941’s Citizen Kane or 1976’s All the President’s Men to 2015’s Spotlight and last year’s The Post.  And most organizations today rely on research to inform their business strategies and decision-making. Whether you’re a detective, a journalist, or a business professional, having access to relevant, trusted content—current and archival traditional and web news; company, industry and executive information; regulatory, legal and public records—empowers you uncover stories that need to be told and conduct the comprehensive investigations that will lead to valuable insights.  What big breakthrough is waiting for you to discover it?

Explore this Topic Further:

  1. Read our previous blog post, “How Distrust in Media has Sparked a Revival in Deep Research & Investigative Journalism.”   
  2. Arrange a free trial of Nexis to access the relevant, credible content that journalists need.
  3. Share this article with your friends and colleagues on LinkedIn to continue the conversation.

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