ST. PAUL — The St. Paul police crime lab plans to seek accreditation through a national board that evaluates forensic testing, a move that would help demonstrate the department has turned around its embattled crime lab.

The city’s police department shut down the lab in 2012, after public defenders’ inquiries disclosed flawed drug-testing practices at the unaccredited St. Paul police crime lab. The city then spent nearly $1 million and a year of work to address the problems, including a review of thousands of criminal cases.

The lab also has hired a new manager, department spokesman Howie Padilla said. She said the department will seek the accreditation later this month.

“Exactly how long that may take to be accredited, we don’t know,” Padilla said. “The process is they have to review our documents. They will schedule some kind of an on-site visit and we’ll go through that.”

Public defenders’ inquiries in 2012 disclosed flawed drug-testing practices at the St. Paul police crime lab. In a review of 100 cases involving drug tests, a consultant hired by the city found errors in most. Another report found numerous examples of latent-fingerprint examiners missing opportunities to identify suspects.

The police department also moved its drug-testing functions to the Minnesota Bureau of Criminal Apprehension’s accredited lab, and made changes to the lab to shore up fingerprint analysis and other work.

After learning of the problems, the lab lost its biggest customers, including the Minnesota State Patrol, and Washington and Dakota counties.

Police Chief Tom Smith said the lab that reopened last August already is breaking major cases. He said it helped recently solve a kidnapping case believed to involve the Mexican Sinaloa drug cartel.

Gov. Mark Dayton signed a bill last month that required crime labs across the state to be accredited to test drugs or conduct other forensic analysis.