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- Sep 30, 2011
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DALLAS — Texas prosecutors left a meeting Friday without the precise roadmap they were looking for when it comes to navigating the more conservative DNA standards used by crime labs in Texas and nationwide.
But they didn't leave the Southwestern Institute of Forensic Sciences empty-handed, they said.
“It would have been nice to see more answers," Inger Chandler, chief of the conviction integrity unit in the Harris County district attorney's office. "As lawyers, we tend to see things in black and white, and we're learning there's a lot of gray."
....Chandler was one of many prosecutors who attended a Texas Forensic Science Commission meeting on how past and future cases could be affected by a new standard in analyzing data involving "mixed DNA." That type of DNA refers to when more than one person's DNA is found on evidence.
While there's no proof that the new standard — adopted by the Texas Department of Public Safety crime labs and other labs used by DA's offices — would exclude a defendant, the new protocol could reduce the likelihood that an individual's DNA is the only source of genetic material left at a crime scene.
In a few hours, experts tried to temper the expectations about DNA testing that were built over more than a decade.
"One of the problems was DNA was called the gold standard," Bruce Budowle, director of the University of Texas Health Science Center's Institute of Applied Genetics, said. "Big mistake."
DNA analysis provides answers, but there has to be rigorous interpretation of DNA results, the experts said.
Lawyers, Scientists Try to Unravel Thorny New DNA Standard
This is how that came about:
This past spring, the FBI notified crime labs there were errors in the data used to calculate the chances that DNA found at a crime scene matched an individual. But it downplayed the impact of the errors on court cases, setting off a low but distinct rumble throughout the criminal justice system nationwide.
After reading the FBI's notice, district attorneys like Galveston County's Jack Roady asked DPS to reassess evidence that had already been tested for use in upcoming trials — this time, using the FBI's corrected data, which was related to population statistics.
"When the FBI sent out the 'pop stat' issue memo, that these were some errors and should not be any issues, I don't have any reason to think they were wrong in that," Roady said.
But a second concern emerged after Roady got his evidence analysis back from one of the eight Texas Department of Public Safety crime labs that tests DNA evidence. Recently, DPS and crime labs nationwide have switched to a more conservative analytical approach when looking at "mixed DNA" — which refers to when more than one individual's DNA is present on evidence.
New Crime Lab Protocol Leads to Reviews of "Mixed DNA" Evidence
Major changes happening.
But they didn't leave the Southwestern Institute of Forensic Sciences empty-handed, they said.
“It would have been nice to see more answers," Inger Chandler, chief of the conviction integrity unit in the Harris County district attorney's office. "As lawyers, we tend to see things in black and white, and we're learning there's a lot of gray."
....Chandler was one of many prosecutors who attended a Texas Forensic Science Commission meeting on how past and future cases could be affected by a new standard in analyzing data involving "mixed DNA." That type of DNA refers to when more than one person's DNA is found on evidence.
While there's no proof that the new standard — adopted by the Texas Department of Public Safety crime labs and other labs used by DA's offices — would exclude a defendant, the new protocol could reduce the likelihood that an individual's DNA is the only source of genetic material left at a crime scene.
In a few hours, experts tried to temper the expectations about DNA testing that were built over more than a decade.
"One of the problems was DNA was called the gold standard," Bruce Budowle, director of the University of Texas Health Science Center's Institute of Applied Genetics, said. "Big mistake."
DNA analysis provides answers, but there has to be rigorous interpretation of DNA results, the experts said.
Lawyers, Scientists Try to Unravel Thorny New DNA Standard
This is how that came about:
This past spring, the FBI notified crime labs there were errors in the data used to calculate the chances that DNA found at a crime scene matched an individual. But it downplayed the impact of the errors on court cases, setting off a low but distinct rumble throughout the criminal justice system nationwide.
After reading the FBI's notice, district attorneys like Galveston County's Jack Roady asked DPS to reassess evidence that had already been tested for use in upcoming trials — this time, using the FBI's corrected data, which was related to population statistics.
"When the FBI sent out the 'pop stat' issue memo, that these were some errors and should not be any issues, I don't have any reason to think they were wrong in that," Roady said.
But a second concern emerged after Roady got his evidence analysis back from one of the eight Texas Department of Public Safety crime labs that tests DNA evidence. Recently, DPS and crime labs nationwide have switched to a more conservative analytical approach when looking at "mixed DNA" — which refers to when more than one individual's DNA is present on evidence.
New Crime Lab Protocol Leads to Reviews of "Mixed DNA" Evidence
Major changes happening.
