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Chris' Blog

The blog of Chris Perri Law, written by Chris Perri and Shannon Perri. Read the latest in exciting cases where justice is served.

Filtering by Category: DNA

The Leading Causes of Wrongful Convictions

Chris Perri

 Photograph by  James Faulkner

Photograph by James Faulkner

No country locks up more people than the United States of America. Even worse, many of those in prison are innocent. According to The Innocence Project, an important criminal justice advocacy group, below are the four leading causes of wrongful convictions.

1. Eye Witness Misidentification is the single greatest cause of wrongful convictions. We know this because later found DNA evidence often proves a witness’s testimony to be inaccurate. Usually, eye witnesses are not trying to lie, but perhaps after viewing a lineup of suspects, they feel pressured to make a choice and then stick to it. Or sometimes, a case is very old, and it’s difficult for a witness to remember exactly how the defendant appeared and to know how they’d appear now. Still, confident eye witness testimony can be very convincing to jurors even though we all know memory is flawed.

2. Improper Forensics is another contributing factor. If a seemingly credible expert gets on the stand and spouts out questionable science, juries are likely to trust them. Further, the mishandling of scientific evidence can lead to major problems. Take for instance when mistakes at the DNA Lab in Austin put the credibility of nearly 5,000 convictions in question. Though forensic science has come a long way, it’s still administered and analyzed by people. Therefore, there is room for major error.

3. False confessions are another huge problem. It can be hard to believe, but many innocent people confess to crimes they did not commit. This is especially true with children, adolescents, and those with mental disabilities. Why do innocent people admit guilt? The reasons vary, but duress, coercion, confusion, or fear of a harsher sentence if they don’t plea are some of the most common reasons.

4. Incentivized Informants/Snitches is the fourth leading cause of wrongful convictions, and it’s easy to understand why. If a witness is paid to testify or is offered something in exchange, such as release from prison or a reduced sentence, their information is less credible. The informant is motivated to say what the prosecution wants to hear.  

Many other factors contribute to wrongful convictions, such as ineffective legal assistance, false reporting, and withheld evidence. The best way to avoid a wrongful conviction is to have a zealous criminal defense attorney by your side from the beginning. That said, if you do find yourself or a loved one wrongfully convicted, don’t lose hope. An experienced post-conviction appellate lawyer can still help. Though overturning a conviction is an uphill battle, it does happen. Chris Perri Law has successfully reversed convictions through both Appeals and Writs.

Whether you’ve just been arrested or just been sentenced, call Chris Perri Law at (512) 917-4378 to discuss your legal options.

Nearly 5,000 Austin Convictions in Limbo due to DNA Lab Errors, But Relief for the Wrongfully Imprisoned Still a Long Ways Off

Chris Perri

 Photograph by University of Michigan DNA Lab

Photograph by University of Michigan DNA Lab

The Austin American-Statesman has thoroughly covered the fallout from the Austin Police Department’s DNA lab closure, but if you haven’t been following the news closely, it’s difficult to find one article that provides the overall picture of what’s going on with the DNA issues in Travis County. Below, I’ve summarized the recent Austin DNA Lab scandal, along with providing a legal perspective on how these revelations might affect people who were convicted on the basis of false DNA evidence.

Recalculations vs. Retesting

In the summer of 2015, the FBI announced that errors in its database might have caused nationwide laboratory miscalculations of the probability that DNA found in evidentiary mixtures matched particular defendants’ known DNA profiles. Here is a blog post I wrote on the subject.

The important takeaway is that while the FBI’s database error affected cases nationwide, it only applied to DNA mixtures, which is a type of sample that contains two or more people’s DNA. If DNA mixture evidence contributed to a defendant’s conviction, then the defendant can request a recalculation of the probability that the mixture contained the defendant’s known DNA profile. Such recalculations do NOT involve any re-testing, as the lab simply uses the corrected database protocols to recalculate the probability of a match. The FBI database issues do not implicate the reliability of the actual testing conducted by the various forensic laboratories.

While government agencies argued that the recalculations would not materially affect any pending cases, these assurances became less credible when recalculations in a Galveston murder case drastically reduced the probability that the defendant was the perpetrator.

Meanwhile, the DNA retesting issue rocked the Austin Police Department (APD) last summer, and it could affect up to 5000 past convictions. The chaos began when the Texas Forensic Science Commission conducted an audit of APD’s DNA Laboratory last spring, and the Commission discovered a host of unreliable scientific practices pervading the lab. Among the highlights:

1.     Improper Stochastic Threshold: DNA labs must adopt guidelines to determine whether their interpretation of each DNA sample is scientifically reliable. The stochastic threshold is the point at which a scientist can reliably interpret DNA in a manner that’s not muddled by random effects, such as allele dropout. At APD’s lab, the scientists used a quantitative baseline (as opposed to a qualitative one) as its stochastic threshold, despite the fact that no peer-reviewed journal had ever accepted such a quant-based threshold. Without a valid stochastic threshold, the lab cannot be certain whether its testing results were merely a product of randomness, as opposed to sound scientific process. Because an improper protocol was used at the very beginning stages of all DNA testing, any of the final interpretative results are unreliable. Garbage in, garbage out.

2.     Suspect or Victim-Driven Testing: Sound scientific method requires that scientists select an unknown sample’s comparison loci (the particular segment of DNA material that will later be compared to the known DNA profiles) without knowledge of which comparison loci are clearest on the known DNA profiles. However, APD’s “scientists” were essentially cheating, as they used the known DNA profiles of suspects and victims in order to determine which loci to examine in the unknown samples. This practice created a bias towards finding a match.

3.     Unclear Use of Protocol Deviation: Lab technicians occasionally deviated from clear technical guidelines when it suited the particular needs of a case. Part of the problem stems from APD’s scientists not remaining independent from the investigative team, as the scientists often felt pressure from investigators to return favorable results. This collusion is one of the main reasons why I’ve advocated an independent lab, and the Travis County judges agreed in a proclamation last December.

4.     Contamination: In one egregious example of incompetence, the Forensic Science Commission observed carry-over contamination between the DNA on a victim’s vaginal swab and the DNA on a suspect’s penile swab, despite the fact that this suspect was later determined to be unrelated to the offense. It took re-testing by a different laboratory before this suspect was cleared for an offense he did not commit.

After the Commission’s report, there was also a revelation that a freezer housing hundreds of DNA samples broke down last spring for eight days, leaving officials uncertain whether evidentiary samples had been damaged.

Somehow, despite these systemic problems at APD’s DNA lab, it received annual accreditations for over a decade. A Statesman article revealed that the accrediting body "did not test if a lab’s scientific processes were appropriate for analyses." That seems like a pretty huge oversight in the accreditation process.

The Fallout

Since the revelation of these monumental problems at APD’s DNA Lab, it has closed down and the testing on all pending cases has been sent to independent labs. However, the problem remains of what to do about the convictions from 2005-2016 that were based on faulty DNA testing. Estimates on the number of cases that need to be reviewed range from 3,600 to 5,000.

The Travis County Commissioners and City Council have been considering options for implementing a materiality review to determine which cases need to have the DNA evidence retested, with cost estimates for this review ranging from $6 million to $14 million. However, as of today, the bureaucrats haven’t made a decision, and they appear to be leaning towards the least costly option. I’ve argued that at a minimum, this materiality review must be independent from the Travis County District Attorney’s Office, which has a conflict of interest by virtue of securing the convictions that are under review.

The critical point right now is that the essential independent materiality review of the thousands of cases hasn’t yet begun, and there’s no telling how long it will take to create an independent commission to conduct the review. Even then, a materiality review will only identify the cases in which DNA evidence was a material contributor to a conviction, and at that point, DNA re-testing will be ordered. Defendants will then have to wait for the DNA re-testing to be completed before they know whether they’re entitled to a new trial. And if they are entitled to a new trial, the defendants will have to wait even more time while an application for writ of habeas corpus circulates through the trial court and the Court of Criminal Appeals.

Given the lack of agreement in political circles about how best to conduct the review and the time lag to implement any proposed solutions, there’s no relief in sight for defendants waiting on Travis County to solve this mess.

How We Can Help

Chris Perri Law has over a decade of experience in reviewing post-conviction cases. If you or a loved one suffered from a conviction involving DNA evidence that was tested by the Austin Police Department, contact our firm to review the case. If your case was not in Austin but involved DNA mixtures, contact our firm about requesting a re-calculation of the probability that the DNA mixture matched the defendant. We advocate for our clients from the beginning stages of the process (DNA materiality review) through the final litigation of the writ of habeas corpus in order to ensure that wrongfully convicted people are set free. 

An update on the recent DNA testing errors

Chris Perri

Update from previous post:

Last week, the Travis County District Attorney’s Office announced that it has formed a Conviction Integrity Unit in order to facilitate the comprehensive review of all cases that might have been affected by the miscalculations of probabilities related to DNA mixtures from 1999-2015. This is definitely a step in the right direction, as many experienced criminal justice practitioners are concerned that the miscalculations could have affected thousands of cases.

If you or a loved one suffered a conviction in a case involving DNA evidence, it’s important to retain an experienced criminal defense attorney to review your case. Chris Perri Law can determine whether your case was potentially affected by the DNA miscalculations and then assist you in obtaining a recalculation of the DNA evidence. Depending on the results, Chris Perri Law can then file a post-conviction writ of habeas corpus seeking to overturn your conviction. Chris Perri Law offers these post-conviction services on both state and federal cases throughout Texas.

Check out Chris Perri’s video interview with Austin’s Fox 7 News for more information about these mind-blowing DNA developments.

Wrongful convictions may have have resulted from crime labs' exaggeration of DNA results

Chris Perri

 

Austin news station, KXAN, interviews Chris Perri about the issue. 

Over the summer, the Texas Forensic Science Commission, which reviews the current standards for physical evidence in Texas criminal courts, discovered that state crime labs were using outdated protocols for analyzing DNA evidence. In particular, the problems occurred in “mixed DNA” test results, where the labs were exaggerating the likelihood that a particular sample matched a defendant’s DNA.

There are two types of DNA profiles that can come from any given DNA sample: “mixed DNA” (also called “mixtures”) and single-source DNA. Mixtures are the most common type of DNA profiles. A mixture occurs when a DNA sample contains DNA from more than one person. For example, if two or more people touched the handle of a firearm, a DNA sample from this handle would likely be a mixture of multiple people’s DNA. In contrast, a “single source” DNA profile exists when only one person contributed the DNA to a sample. In the case of single-source DNA profiles, matching a given person to the sample is similar to matching a person to a fingerprint left at a crime scene. However, because there are numerous types of DNA profiles that could combine to create a mixture, the probability that a random person besides the defendant could have contributed to this mixture is higher than in the case of single-source DNA profiles.

The Texas Forensic Science Commission recently revealed that state labs have been reporting inaccurately high probabilities of matches between defendants and mixed DNA samples since 1999.

An example of a recent Galveston murder case illustrates the problem. The crime lab reported that the defendant contributed DNA to a mixture from the crime scene, with a certainty of more than a million to one. However, it turns out that the lab was using outdated protocols, and the certainty is actually just forty to one. This means that if you selected 1,000 random people, 25 of them would match the DNA found at the crime scene. That’s hardly enough evidence to convict someone beyond a reasonable doubt.

Everyone knows that eyewitness testimony can be fallible, so prosecutors have placed great weight on scientific DNA evidence when prosecuting cases since the advent of DNA testing in the mid-1990s. Due to jurors learning about the infallibility of DNA science from television crime shows (the CSI effect), jurors often convict defendants on the basis of DNA evidence alone. Now that we know that scientists were inaccurately reporting the probability that crime scene DNA matched particular defendants, many convictions over the last fifteen years may have been based on false evidence, and innocent people could be behind bars.

Police labs and prosecutors’ offices have downplayed the severity of the problem. For example, according to a memorandum from Art Acevedo, the chief of the Austin Police Department, the inaccurate reporting is “unlikely to materially affect any assessment of evidential value.” Court orders will be required in order for the labs to re-test samples to determine accurate statistical probabilities of a match between crime scene samples and defendants’ DNA.

I’m concerned that prosecutors and police forces are sweeping this issue under the rug. Rather than re-assure the public with rhetoric, they should create task forces to revisit every case where DNA played a role in obtaining a conviction, and the labs should recalculate statistical probabilities in all of those cases. After all, it was the State that put false evidence before juries, so the burden should be on the State to correct the problem and regain the public’s confidence that innocent people aren’t behind bars.

If you or a loved one suffered a criminal conviction as a result of mixed DNA test results, you should contact Chris Perri Law to determine whether your case could have been affected by inaccurate scientific testimony. Check out the articles below for more information on this unique and unsettling issue:

http://www.everythinglubbock.com/news/state-regional/new-dna-standards-could-lead-to-thousands-of-retrials-in-texas

http://www.npr.org/2015/10/09/447202433/-great-pause-among-forensic-scientists-as-dna-proves-fallible?utm_source=facebook.com&utm_medium=social&utm_campaign=npr&utm_term=nprnews&utm_content=202509