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forensics

Why DNA Evidence is Less Reliable than People Believe

By Peek & Toland on January 25, 2018

DNA evidence has been central to criminal trials for almost 40 years. Many people are led to believe it’s almost foolproof. This is a dangerous presumption. In fact, DNA evidence is riddled with potential flaws.

An article in Popular Science cited a Gallup poll that found 58 percent of people believe DNA evidence is extremely reliable.

This perception has been challenged by recent revelations. Two years ago, Frontline noted how DNA evidence can lead juries astray and lead to wrongful convictions.

That’s not to say DNA is inherently unreliable. Compared to many other forensic techniques that have been debunked, DNA has a high accuracy rate.

DNA evidence may not be reliable

DNA evidence may be unreliable

DNA is certainly unequivocal under optimal conditions. The Popular Science article says when investigators have large quantities of a suspect’s well-preserved genes if it’s obvious how DNA arrived at the crime scene, and labs sequencing the sample don’t make any mistakes, the evidence should be foolproof.

Unfortunately, these optimal conditions are met in very few cases. Often when DNA evidence is presented to a court, there is some ambiguity. Juries may not realize that gray areas exist.

The article points out DNA samples from crime scenes are imperfect and the DNA breaks down. This makes it extremely challenging to get a 100 percent match.

But when a match exists, it’s not possible to know how the crime scene DNA sample got there in the first place. Scientists are not sure how DNA travels.

Many of the body’s cells contain DNA. We shed it wherever we go. The article points out that under certain circumstances, these cells can end up in places we have never been.

Also, it’s not possible to know from DNA how much earlier it was deposited. So DNA at a murder scene left there six months earlier may become implicated in the investigation.

Over the last three years, officials became increasingly concerned about how DNA evidence was treated in labs.

Two years ago, The FBI informed crime labs across the nation that it discovered mistakes in data used by forensic scientists. The errors related to the chances that genetic evidence found at a crime scene matched a particular individual in thousands of cases the Washington Post reported.

Initially, the FBI discounted fears that the flawed methodology could undermine cases. Jurors were informed the chances that DNA belonged to anyone other than the defendant if there was a match was one in more than a billion. It later emerged that the odds were more like one in 100 in many cases, a marked difference.

Austin Police Department’s crime lab faced recalculating statistics on about half of almost 1,300 Travis County cases. Problems at the lab that resulted in its closure last year exacerbated the issues.

If you have been charged with a crime you should be aware any forensic evidence against you may be unreliable. An experienced criminal defense lawyer can expose flaws in this evidence. Please call us at (512) 474-4445.

Posted in Criminal Defense

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Austin DNA Lab Flouted Standards for Years, Report Finds

By Peek & Toland on May 29, 2017

We have written before about the closure of the Austin DNA lab and speculation that it would open again in early 2017.

However, hopes for a speedy reopening of the lab have been derailed. A recent report found the lab bucked DNA standards for years but was given a pass.

The new set of DNA guidelines that were drawn up in 2010, were noted in the Statesman.

The influential Scientific Working Group on DNA Analysis Methods came to the conclusion that analysts should concentrate on the quality of a sample as opposed to the quantity of the evidence gathered at a crime scene, before deciding if they could confidently create a genetic profile.

The Austin DNA lab closed last year following concenrs

Austin DNA lab is under fire

The article highlighted the little-known but alarming fact that forensic labs in the United States are not formally regulated. Instead, they are subject to a set of evolving standards.

The working group in tandem with the National Institute of Standards and Technology drew up best practices.

Over the following five years, the organizations held many training sessions, visited labs and carried out surveys.

The experts warned using older methods of DNA analysis led laboratories to be overconfident in their findings,. The result was improper criminal prosecutions. The report said by 2015, every lab in the United States adopted the improved methods except the Austin DNA lab.

The lab in Austin appeared to be working fast on its caseload. Then last summer, former Austin police chief Art Acevedo said the lab would close temporarily to allow analysts to correct problems uncovered in the reviews.

Austin DNA Lab Closure Could be Indefinite

The police department ordered the closure after concerns were raised by the Texas Forensic Science Commission. It found a lack of properly trained supervision and noted the requirement for the staff at the lab to learn the new federally required way of verifying DNA evidence.

Although the lab was meant to be closed temporarily, in December officials said it would close indefinitely.

The Statesman article cited interviews with workers that suggested the lab’s problems went back long before 2016.

Donna Stanley, the former DPS analyst originally hired to get the Austin lab off the ground more than 10 years ago, said inadequate methods were used for years.

The Statesman article warned a cluster of forensic facilities in Texas and across the United States suffered failures in the last decade. Shortcomings ranged from missing or stolen evidence, to substandard science and even faked results. These scandals have raised doubts about the science used to secure thousands of convictions.

Of just over 300 Texans exonerated for crimes, 142 — nearly half — were convicted based on misleading or false forensic evidence, according to the National Registry of Exonerations.

A report on Channel 5 quoted police sources saying the DNA lab in Austin may not now re-open until 2018.

As experienced Austin criminal defense lawyers, we are alarmed by these revelations. If you believe your conviction is based on faulty forensic evidence, please contact us here.

Posted in Criminal Defense

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How Hair Comparison Evidence was Discredited

By Peek & Toland on November 25, 2016

Hair comparison evidence has been used to convict hundreds of people nationwide. Three years ago, the FBI admitted the forensic technique is unreliable.

For many people who were jailed, the realization came too late. In a recent article, The Guardian highlighted the case of George Perrot who spent almost three decades in prison due to the evidence derived from a single hair.

An FBI agent recovered the hair from the sheet of the bed a 78-year-old woman who was raped by a burglar in Massachusetts in 1985.

Hair comparison evidence has become discredited

No physical evidence tied Perrot, who was just 17 at the time, to the crime scene. There was no semen or blood evidence, rendering a DNA match impossible.

Even the victim said Perrot didn’t look anything like her attacker. However, he was put on trial in 1992. An FBI agent proclaimed himself to be an expert in hair evidence. He said a hair recovered from the bed sheet matched that of Perrot.

The agent told the jury he was an expert in hair and textile fibers. His testimony was strong and he presented himself as such a convincing witness that the jury convicted Perrot.

Hair Comparison Evidence is Discredited

Three years ago in July 2013, the FBI admitted a major retreat from “hair comparison evidence.”

For decades its investigators learned the technique and used it in tens of thousands of cases. However, the 2013 statement revealed the evidence is scientifically invalid.

The FBI stated:

  • A microscopic analysis of hair analysis is not able to scientifically distinguish one suspect to the exclusion of all other people.
  • It is impossible to give any statistical credence to comparisons to that pointed to a likelihood of the hair coming from a specific source.
  • The number of previous hair comparison tests carried out by expert witnesses should not be used as a factor in court to demonstrate a case for how a hair belonged to a specific person.

The scale of the miscarriage of justice over hair comparison evidence may be huge. A report in the Washington Post stated there were 28 examiners employed by the FBI Laboratory’s microscopic hair comparison unit. All but two overstated forensic matches to favor the prosecution in more than 95 percent of 268 trials. Other are still to be reviewed, stated the National Association of Criminal Defense Lawyers (NACDL).

At Peek & Toland we provide vigorous representation for people who have been charged with crimes in and around Austin. Even if the evidence seems to be stacked against you, it may be flawed. A criminal defense attorney will challenge suspect evidence. Call us at (512) 474-4445.

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