A nearly yearlong hearing into the scientific credibility of St. Paul police's troubled crime lab took another turn Friday when defense attorneys dropped plans to submit findings from an independent audit of the lab and instead submitted a Texas court of appeals decision about the Houston crime lab.

Public defender Lauri Traub argued that the Texas decision, which vacated 12 post-conviction drug cases because a criminalist was found to have compromised the integrity of evidence, "illustrates exactly what we've been trying to say."

Traub and public defender Pam King are representing three clients in Dakota County District Court who are challenging how St. Paul's crime lab handled drug evidence that was eventually retested at the Minnesota Bureau of Criminal Apprehension (BCA). The BCA results supported the police's positive findings of drugs in all three cases. Traub and King are asking Judge Kathryn Davis Messerich to prohibit the admission of the BCA results in court because of possible contamination at the police lab.

Chief Deputy Dakota County Attorney Phil Prokopowicz strongly objected to Traub's attempt to submit the Texas decision, noting that the case involved a criminalist accused of faking drug reports, which is "significantly different" from allegations of scientific failure facing the lab.

Messerich decided not to accept the Texas decision into the Dakota County case. Messerich has 90 days to issue her decision, but vowed to rule sooner.

Prosecutors from Dakota, Ramsey and Washington counties took the unusual step in August of voluntarily throwing out police lab results in the contested cases because of testimony that showed criminalists didn't follow any written standard operating procedures, weren't properly trained to use a key testing instrument and were using a testing process that wasn't scientifically vetted.

Testimony also showed that criminalists were undertrained, testing instruments were poorly maintained and reports were not written in accordance with scientific standards. The city later hired consultants whose audits of the lab were equally critical of its operations.

King said Friday that they dropped the audit information because it duplicated previous testimony.

The lab has undergone a major overhaul, including the hiring of a civilian lab manager with scientific experience. Drug testing will be moved to the accredited BCA lab, and Smith has said the city will seek accreditation for the police lab's fingerprinting and crime scene work.

The BCA retested 197 cases first tested by police; three results contradicted police findings. One case was dropped because of the discrepancy.

About 1,700 cases are being reviewed by the state public defender's office for possible post-conviction relief, and county attorneys are dismissing or striking deals on some cases. Prokopowicz said his office has either reduced or dismissed charges in 40 cases involving trace amounts of suspected drugs.

Chao Xiong • 612-270-4708

Twitter: @ChaoStrib