DULUTH – Carlton County's former top prosecutor has been disbarred by the Minnesota Supreme Court for professional misconduct.

Thomas Pertler, who was the county attorney from 2005 to 2018, is no longer allowed to practice law in the state after failing to disclose police misconduct while in office, which led to the dismissal of 19 pending criminal cases and the retroactive dismissal of eight convictions.

The Supreme Court's order said Pertler also failed to train staff and implement a Brady policy, which deals with the disclosure of police misconduct and credibility during court proceedings.

Pertler, who "unconditionally admits the allegations" per the Supreme Court order, could not be reached for comment.

The Office of Lawyers Professional Responsibility, a state agency that handles professional conduct complaints, launched a petition to discipline Pertler this summer. Pertler, 56, will pay $900 as part of the order.

The discipline stems from a 2016 investigation into misconduct by Cloquet Police Cpl. Scott Beckman. The police chief later found the claims were credible and told Pertler, according to the disbarment petition. Pertler "did not advise assistant Carlton County attorneys ... of Cpl. Beckman's misconduct and resulting discipline," the petition states.

Lauri Ketola defeated Pertler in the November 2018 election, after which Pertler stopped coming in to work despite his term lasting until Jan. 6, 2019.

Assistant County Attorney Jeffrey Boucher that winter implemented a Brady policy and wrote that "the findings in question must be disclosed in every case in which Officer Scott Beckman is involved."

Beckman, who had also been suspended for misconduct in 2012, was fired by the city in December 2018.

Among the 19 charges dismissed due to the revelation of Beckman's misconduct were several domestic violence cases that saw pretrial protective orders lifted, potentially putting victims at risk.

Pertler was first admitted to the Minnesota Bar in 1990. He was appointed county attorney in 2005 and was elected in 2006, 2010 and 2014. Pertler was the lead prosecutor on the high-profile Donald Blom case in 2000. Blom was convicted of kidnapping 19-year-old Katie Poirier from a Moose Lake gas station and murdering her.

Pertler pleaded guilty in 2012 to refusing to submit to a chemical test after being pulled over in Duluth on suspicion of drunken driving, according to court records.

Brooks Johnson • 218-491-6496