A suspect is in custody after a man was shot dead in a southern Minnesota state park late Tuesday.

A man called 911 around 9:15 p.m. to report that he had shot another man at Myre-Big Island State Park near Albert Lea, according to the Freeborn County Sheriff's Office.

The caller surrendered peacefully when officers arrived at the park, and turned over a pistol that authorities believe was the weapon used in the shooting.

Neither man was identified by authorities Wednesday, and it's not yet known if they knew each other or what preceded the shooting. The men both once lived in Omaha, Neb., said Freeborn County Sheriff Kurt Freitag. The victim has lived in Freeborn County since May of this year, the sheriff said.

The suspect is being held in Freeborn County jail on suspicion of second-degree murder.

The only known witness is the alleged shooter's wife, who heard the shots but didn't see them being fired, Freitag said.

The alleged shooter told authorities that he shot the weapon in self-defense and that the other man had a bat. The dead man was found in the driver's seat of his car, with the windows rolled up, the doors locked, his foot on the brake and the car in reverse, the sheriff said.

Early investigation indicated that neither man had a history of criminal activity in the area, said Freitag. Speaking of the alleged shooter, the sheriff added: "He's not up on our radar."

The Minnesota Bureau of Criminal Apprehension was on the scene Wednesday to help with the investigation.