Rare look inside state crime labs reveals recurring DNA test problems

[icymist]

Thursday, July 22, 2004

Rare look inside state crime labs reveals recurring DNA test problems

By RUTH TEICHROEB
SEATTLE POST-INTELLIGENCER REPORTER

For the detective working the case, it looked like a sure thing. The 58-year-old suspect had confessed to raping his young niece. He had a prior sex-crime conviction.

<snip>

Forensic scientist Mike Dornan had bungled the test, accidentally contaminating the child's clothing with DNA from another case he'd been working on.

<snip>

Forensic scientists tainted tests with their own DNA in eight of the 23 cases. They made mistakes in six others, from throwing out evidence swabs to misreading results, fingering the wrong rape suspect. Tests were contaminated by DNA from unrelated cases in three examinations, and between evidence in the same case in another. The source of contamination in five other tests is unknown.

<snip>

A decade ago, DNA tests needed a quarter-size stain of blood or semen to produce a strong match and took about six weeks to complete. Today, the lab needs only about 40 human cells, invisible to the naked eye, to produce a DNA profile using an extremely sensitive method called "polymerase chain-reaction," or PCR.

<snip>

DNA results are examined by defense experts who review lab notes, analyze computer data and rerun tests to double-check accuracy. Experts also observe DNA testing at the lab when a sample is too small to divide.

Yet critics say many defense attorneys are easily intimidated by DNA cases and don't dig deeper when a suspect has been "matched" to a crime. Instead, they cut the best deal they can.

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[icymist]

1. DNA testing mistakes at the State Patrol crime labs (related article)

Thursday, July 22, 2004

DNA testing mistakes at the State Patrol crime labs

SEATTLE POST-INTELLIGENCER STAFF

Contamination and other errors in DNA analysis have occurred at the Washington State Patrol crime labs, most of it the result of sloppy work.

The most common problems are cross-contamination by microscopic traces of unrelated evidence and forensic scientists accidentally mixing their own DNA with the sample being tested. That can happen, for example, when the analyst talks while handling a sample, leaving an invisible deposit of saliva.

Below are the 23 cases of contamination or errors in major criminal cases the lab system has admitted to, according to State Patrol and court documents:

EXAMPLE NO. 1


Problem: Cross-contamination


When and where: July 2002, Spokane lab


Forensic scientist: Lisa Turpen


Case: child rape


What happened: Turpen contaminated one of four vaginal swabs with semen from a positive control sample. Corrected report issued almost two years later in March 2004. ....Yakima prosecutors offered plea deal during the trial, with defendant pleading guilty to two gross misdemeanors. Turpen's mistake was a factor, according to defense.

More at this

[icymist]

2. Produce crime lab error rates, some urge (related article)

Thursday, July 22, 2004

Produce crime lab error rates, some urge
But defense attorneys would misuse data, scientists counter

By RUTH TEICHROEB
SEATTLE POST-INTELLIGENCER REPORTER

The high stakes of DNA testing have prompted debate about whether the nation's crime labs should have to produce error rates. Defense experts and academics say such a statistic would provide a valid way to gauge the reliability of a lab's work. Forensic scientists in state-run and private crime labs say error rates would be meaningless.

A generic error rate for a lab doesn't tell you whether a specific DNA test is correct, said Gary Shutler, who oversees DNA testing for the Washington crime lab system.

Defense attorneys would use labwide error rates to try to undermine every DNA result, Shutler said. Even defining what type of contamination or errors should be included in an error rate would be difficult.

But some experts argue that error rates should be a factor in weighing DNA evidence in court -- something prosecutors, police and crime lab officials have a "vested interest" in avoiding.

More at this

[Archae]

3. This happened in Texas too.

A crime lab for a Texas city was regularly botching and even falsifying DNA testing.

http://www.chron.com/content/chronicle/special/03/crimelab/

[icymist]

4. Whoa! Now that's contamination!

It seems that the infallible DNA 'evidence' has now met it's match. In reading in the first article, contamination can happen by someone sneezing nearby, scientists holding a conversation while conducting testing, and just plain sloppiness! I think the technology has leaped passed the laws (again)!

on edit to clear HTML's

[Devils Advocate NZ]

5. But we all know OJ did it, right?

I mean, the DNA evidence in his case was AIRTIGHT!!!

[icymist]

6. OJ's case was a decade ago when the evidence was harder to contaminate.

However, it WAS in L.A. Who knows!

[Devils Advocate NZ]

7. Harder to contaminate?

Actually, if I recall correctly, the OJ case was one of the first to use PCR which was the type of test used in the cases mentioned in the article.

The whole point of the defence was that these tests MAGNIFIED errors so greatly that the resulting findings were untrustworthy. It seems they were right.

[icymist]

9. I wasn't aware that OJ's case was one of the first to use the PCR...

test method. Since that was such a highly televised public case, you would think that some of the 'bugs' of this method be addressed instead of seeing similar issues being raised ten years later. After all, it's only the lives of our citizens and the credibility of our crime labs that we're talking about.

[w4rma]

8. Chemistry can be tough stuff. Lots to pay attention too and chemists

don't really make enough money for the painstaking work they do, imho.

[Bridget Burke]

10. Remember recent proposals for massive DNA banks?

Anybody arrested for anything (guilty or not) would have their DNA stored. Then, any DNA evidence obtained from a crime scene could be compared against those on file & an arrest could be made. How simple!

Obviously, lots of people would end up being taken in on very bad evidence, indeed.

[icymist]

11. (related story) Oversight of crime-lab staff has often been lax

Friday, July 23, 2004

Oversight of crime-lab staff has often been lax

By RUTH TEICHROEB
SEATTLE POST-INTELLIGENCER REPORTER

A crime lab chemist snorts heroin on the job for months, stealing the drug from evidence he was testing.

A senior DNA analyst lies to a defense attorney, fearing his testing error would be used to undermine a case against a suspected rapist.

A forensic scientist is accused of sloppy drug analysis, after a national watchdog group complains about his misleading court testimony.

In all of these cases, internal checks and balances failed. The system for double-checking work broke down in one case. In another, officials overlooked warning signs until faced with a crisis. And the work of discredited senior staffers was almost never audited, an investigation by the Seattle Post-Intelligencer found.

A close look at the Washington State Patrol crime labs reveals a stressed system in which officials have been slow to deal with misconduct by long-time employees -- dating back to one of the first scientists hired more than 30 years ago.

More at this

[icymist]

12. (related story) Crime labs too beholden to prosecutors, critics say

Friday, July 23, 2004

Crime labs too beholden to prosecutors, critics say

By RUTH TEICHROEB
SEATTLE POST-INTELLIGENCER REPORTER

Flawed forensic work not only leads to wrongful convictions, it leaves criminals on the street.

That's a good reason to care about reforming state-run crime labs, legal experts say.

"What you have in this country is an epidemic of crime lab scandals," said Barry Scheck, president-elect of the National Association of Criminal Defense Lawyers.

Scheck is co-founder of the New-York based Innocence Project, a group that has helped exonerate 145 wrongfully convicted prisoners.

"Forensic science has to be an independent third force in the justice system," he said, "not beholden to prosecutors and police."

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