Because evidence in drug cases was first handled by maligned St. Paul police crime lab, they want to block its admissibility in court.
Defense attorneys argue that drug evidence tested by the St. Paul police crime lab and then retested at a different lab should not be allowed in court because prosecutors failed to show that contamination did not happen at the police lab.
In a memorandum filed Wednesday, public defenders Lauri Traub and Christine Funk said the state shifted the burden of proof onto them when it stated that they "failed to identify any direct evidence of contamination or tampering." It was the state's job to prove that the police lab's practices complied with appropriate scientific standards and controls, Traub and Funk wrote.
The attorneys are trying to stop samples retested by the Minnesota Bureau of Criminal Apprehension (BCA) from being admitted as evidence in four Dakota County District Court drug cases. When testimony in July revealed widespread problems with the police lab's practices, prosecutors voluntarily threw out the police results, opting to use evidence retested by the BCA.
Defense attorneys argued that the BCA results are not reliable because the evidence originated at the police lab, where practices were suspect.
"It is not credible for the State to argue that contamination was not a possibility while evidence was in the St. Paul Police Department Crime Lab after conceding that results from this lab would no longer be offered as evidence in court," the attorneys wrote.
Testimony by police lab criminalists revealed that there were no written standard operating procedures for evidence handling or testing, no vetting of questionable test results and poor maintenance of testing instruments. Lab staff did not conduct validation studies to show that their workplace surfaces and testing instruments were free of contamination, nor did they meticulously document their testing process, which is mandated for accredited labs. The police lab is unaccredited. The BCA lab is accredited.
In a protracted Frye-Mack hearing that started during the summer, Traub and Funk called two industry experts who testified that the police lab's practices were unacceptable in the wider scientific community. A Frye-Mack hearing is a pretrial session to determine the scientific credibility of evidence.
The state's argument for using the BCA results rests on the similarity between some police lab and BCA practices. Criminalists from both labs testified that they use their own discretion about when, how and how often they cleaned their desks and tools. In both labs, criminalists also left unsealed evidence in one room while testing samples in another room.
Chief Deputy Dakota County Attorney Phil Prokopowicz wrote in his memorandum filed in late November that the labs had "strikingly similar" practices.
"Similarity does not establish that contamination did not occur" in St. Paul, Traub and Funk wrote.
Testimony showed that testing instruments were clogged with white substances that could have been drugs, that the instruments were not properly vented, possibly spewing drugs back into the room, and that they were not routinely cleaned, they wrote.
The BCA's test results in the four contested Dakota County cases supported St. Paul's initial findings. But the labs contradicted each other in two unrelated cases. In one, the BCA found a controlled substance in a sample that St. Paul found negative for drugs. In another, a sample that St. Paul identified as methamphetamine was retested by the BCA and found not to be a narcotic. That case was dismissed.
Staff writer Kevin Duchschere contributed to this report.
Chao Xiong • 612-270-4708 • Twitter: @ChaoStrib