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Law Enforcement Agencies Still Struggling to Reduce DNA Backlog

DNA Tracker: Crime Labs and Their DNA Backlog

Sept. 8: This post has been updated with new backlog numbers for August.

At least 350,000 DNA samples from murder and rape cases remain untested, according to the federal government's best estimates.

The story behind the DNA sample backlog — and the uptick in sample collection that is partially responsible — is one that we've been exploring for months, with investigations published in partnership with Politico, the Los Angeles Times and the Huffington Post Investigative Fund.

There's no one cause for the surge in untested samples. But in May we detailed how much of it can be traced to new federal and state laws requiring DNA samples from people convicted of — or simply arrested for — nonviolent crimes, including shoplifting. (Check out our map that breaks down the DNA collection laws in various states.) Because of these laws, underfunded and understaffed crime labs are now flooded with DNA samples.

In June, ProPublica began tracking five DNA labs to see just how well they're keeping up with efforts to reduce their backlogs. Our latest findings can be found here, and they indicate that little progress has been made.


The FBI lab's backlog has grown as federal DNA collection laws expanded in recent years. Since a new law went into effect earlier this year, the lab has been receiving samples from anyone arrested for a federal crime. The new law also ordered federal agents to take DNA samples from people they detain, typically immigrants suspected of being in the United States unlawfully. Unlike the other labs we are following, the FBI releases its data only on a quarterly basis.

What they are doing about it: The lab is using new robotic systems that will eventually allow it to process 120,000 samples every month, a spokeswoman said.

Crime Scene Case Backlog 'Offender' Backlog
March 2,000 March 293,000
June 1,990 June 293,497

Los Angeles Police Department (LAPD)

LAPD has one of the largest backlogs in the country. (See here for our coverage of LAPD's backlog troubles.) The statistics provided to us by LAPD are only for unprocessed rape kits — DNA samples taken from arrestees or convicts are processed by the California Department of Justice Crime Lab.

What they are doing about it: LAPD began chipping away at its backlog in January after hiring more lab technicians and outsourcing scores of rape kits to private labs for testing. The department hopes to reduce its backlog within four years.

Rape Kit Backlog
May 5,008
June 4,464
July 3,589

California Department of Justice

The California DOJ's lab has one of the largest DNA backlogs of any state lab. Its backlog has boomed since Prop. 69, which mandates DNA collection from arrestees, went into effect in January 2009.

What they are doing about it: A spokesman with California’s Department of Justice says that at any given time 30,000 of its samples can be classified as "in process." The state has also been hiring more scientists and might eventually outsource samples to private labs, a lab official said. The lab presently has no target date for reducing the amount of unprocessed evidence.

Crime Scene Case Backlog 'Offender' Backlog
May 210 May 53,590
June 150 June 61,611
July 230 July 60,815

Illinois State Police

In May, the Illinois legislature narrowly defeated a bill that would have mandated DNA collection from arrestees. That bill could be reintroduced soon, but the state presently has no backlog of DNA samples collected from arrestees or convicts. Meanwhile, a state audit found that the lab reported bogus DNA backlog numbers for several years, leading former Gov. Rod Blagojevich to wrongly declare in 2005 that the backlog was eliminated.

What they are doing about it: The lab is using several methods to cut into the backlog, including hiring more scientists and using robots to speed the testing process. The lab estimates that a scientist using a robot can analyze more cases in about one week than a scientist working manually can analyze in a couple months.

Note: This lab does not have an "offender" backlog.

Crime Scene Case Backlog
May 1,227
June 1,188
July 749
August 798

Virginia Department of Forensic Sciences

Virginia's government was among the first to require DNA samples from arrestees and has no arrestee sample backlog. Advocates for expanded DNA testing point to the Virginia lab as a model: a lab that can handle samples from wide swaths of the population where the arrestee samples are prioritized so they can be analyzed before a suspect is released. Its case backlog includes several dozen cases in a Virginia post-conviction DNA testing project that involves decades-old evidence. The program's goal, a lab spokesman said, is to identify people who may have been wrongfully convicted.

What they are doing about it: The lab doesn't have a target date for eliminating the backlog. A spokesman said the lab is working "consistently to minimize the number of cases affected so we can best serve the citizens of the Commonwealth."

Crime Scene Case Backlog Convicted Felon Backlog
May 1,038    
June 968    
July 1,035 July 6,507

Compiled by Ben Protess and Emily Witt, ProPublica

Update: This post has been updated to reflect that the Virginia Department of Forensic Sciences does not have an arrestee backlog but does have a convicted offender backlog.

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