A motorcyclist accidentally shot by an Eden Prairie police officer is pursuing a lawsuit against the department.

Matthew Hovland-Knase, 22, of Bloomington, led police on a chase at 3 a.m. on June 20 that reached speeds of almost 100 miles per hour before stopping at Eden Prairie Road near North and South Lund roads. Sgt. Lonnie Soppeland got out of his squad car with his gun drawn — protocol for high-risk stops, he told investigators — but the gun went off, shooting the motorcyclist’s arm.

According to documents released to the Star Tribune on Friday by the Hennepin County Sheriff’s Office, Soppeland told investigators that firearm training earlier that month contributed to the unintentional discharge due to the muscle memory of squeezing the trigger.

“My plan was to hold the suspect where he was until back up arrived,” he told investigators three days later. “ … It was not my conscious choice to discharge my firearm. This all happened very fast, maybe within a matter of a second. I could feel the effect of the adrenaline.”

Soppeland immediately holstered the gun and ran to Hovland-Knase to render first aid and call for an ­ambulance.

Hovland-Knase’s attorney, Jim Schwebel, said he will pursue a civil case against police to cover medical expenses.

“I feel sorry for him; he screwed up,” he said of Soppeland. But a gun “doesn’t go off unless you intend it … that’s firearms 101. When you get pulled over, you don’t expect to be shot.”

Hovland-Knase was convicted of a gross misdemeanor for fleeing an officer. A friend told police he borrowed the motorcycle after drinking at a bar. According to the investigation, his blood-alcohol content was .05 percent, under the legal driving limit of .08.

Soppeland, who has worked at the Eden Prairie Police Department since 2005, returned to work after being on administrative duties during the investigation.