MINNEAPOLIS (WCCO) – A Minnesota law professor is questioning the state’s justice system and evidence labs following the controversy surrounding the St. Paul Police Department’s Crime Lab.

“It could mean that an innocent person is in prison, which I think is the worst case scenario,” said Bradford Colbert, a lawyer and professor at William Mitchell College of Law. “That’s certainly what it could mean based on false evidence.”

Colbert said he’s most concerned with past drug cases that the lab has tested.

His comments come after reports of shoddy procedures and now an internal review of the lab. One expert said the lab’s drug tests were insufficient and done by untrained analysts.

“The reliability issues are in question,” said Ramsey County Attorney John Choi.

Choi and his two colleagues in Washington and Dakota counties, James Backstrom and Peter Orput respectively, have decided to retest samples of pending cases. These cases will be sent to the State Crime Lab at the Minnesota Bureau of Criminal Apprehension.

Retesting will start immediately on nearly 400 cases, starting with people already in jail. It’ll then move on based on the level of the offense and the date on which they happened.

“The results of those retests…hundreds of retests that will happens…will tell us a lot about what we need to do as it relates to justice for those past cases,” Choi said.

Prosecutors said that they might have to drop some pending cases if the evidence can’t be retested. Some samples, they say, might be too small to run again.

Choi and his colleagues in Dakota and Washington counties are most concerned with pending cases. But Colbert, the professor, believes past ones are the heart of the problem.

Colbert said that it could mean looking at past guilty pleas and tried cases where crime lab scientists have testified.