A federal judge in St. Paul has dismissed a lawsuit filed by St. Joseph, Minn., resident Ryan Larson, who sued Stearns County authorities alleging that they violated his constitutional rights when they arrested him in connection with the fatal shooting of Cold Spring police officer Tom Decker in 2012.

U.S. District Judge Paul Magnuson issued an order Nov. 13 dismissing the case, ruling that the law enforcement officers named as defendants had a "qualified immunity from prosecution" and that prosecutors had an absolute immunity from civil liability arising from their official actions.

To successfully sue police, Larson would have to have shown that their actions violated clearly established constitutional rights, Magnuson said. He failed to do so, so the officers were entitled to summary judgment and the case must be dismissed, he said.

Larson's claims against Stearns County Attorney Janelle Kendall are barred by law, Magnuson said.

"Kendall is entitled to absolute immunity for approving search warrant applications and applying to extend Larson's detention, because she was acting as an officer of the court," he wrote.

Larson has been representing himself in the case since May. He could not be reached Monday for comment.

Decker was killed Nov. 29, 2012, after responding as backup to a call in Cold Spring, a city of 4,025 residents about 65 miles northwest of Minneapolis. Larson lived in an apartment above the shooting scene and was the subject of the call from his mother, who couldn't reach him. Police smashed down his door while he was sleeping and arrested him. He was named a suspect in Decker's killing and held for five days without charges.

Devon Jacob, one of Larson's lawyers when the lawsuit was filed, had alleged that investigators "intentionally misled the court in a sworn affidavit" to obtain a search warrant. They swabbed Larson's hands for gunshot residue and found none but neglected to include that information in the affidavit, Jacob said. The other officer, Greg Reiter, who called Decker to the scene, "did not immediately report the shooting, pursue the suspect or check on Decker's welfare," he said.

The lawsuit alleged that authorities violated his rights under the Fourth and Fourteenth amendments to the Constitution that protect individuals from unwarranted arrest, search and seizure, and assert their rights to due process under law.

Larson had to quit school. His reputation and employment possibilities were ruined by false allegations, his attorney said. He was diagnosed as having PTSD. It wasn't until August 2013 that the Bureau of Criminal Apprehension said Eric Thomes, who killed himself the previous January, was the probable shooter.