Public defenders challenging the validity of cases involving the St. Paul Police Crime Lab asked a judge Friday, May 3, to throw out drug evidence handled by the lab, saying poor procedures tainted it beyond admissibility. Prosecutors said there's no evidence that happened -- and that Friday's hearing wasn't the proper place to settle the issue. The hearing was supposed to focus on whether testing devices in the lab, which independent reports said were in poor condition and were used improperly, could have contaminated other evidence with dust and other refuse from the drugs being tested. Lauri Traub, a public defender representing a handful of defendants, said concerns over those machines and the overall condition of the lab rendered evidence that entered the lab tainted and inadmissible in court. She pointed to recent Texas Court of Appeals cases in which the court threw out drug evidence from a lab where an analyst used improper procedures and barred retests of the same evidence by other labs because it might be contaminated. Traub asked Dakota County District Judge Kathryn Messerich to apply a similar standard. But Dakota County Chief Deputy Attorney Phil Prokopowicz said that while contamination was possible, "there's no evidence of it" in the case at hand. Retests of crime lab evidence haven't shown traces of other drugs or evidence of contamination, he said.