BISMARCK — A Bismarck man accused of killing another man outside a marina told investigators he was tired of the victim making fun of his struggles with mental health, according to a criminal complaint.

Diego Antonio Ashton, 28, appeared Monday, Oct. 26, in Burleigh County District Court on a Class AA felony of murder in connection to the shooting death of 47-year-old Robert Becker of Bismarck. If found guilty, Ashton could face up to life in prison without parole.

Court documents allege Ashton shot Becker multiple times shortly before 9 p.m. Friday, Oct. 23, at the Misty Waters Marina, along the Missouri River at 5800 Burnt Creek Loop, about 4 miles northwest of Bismarck.

According to the complaint:

Ashton said he drank alcohol before the shooting and asked Becker for a ride because he didn't want to drink and drive.

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During the trip, Ashton told Becker about how he was feeling, and Ashton told investigators Becker gave him a hard time and made fun of his mental health struggles.

Becker laughed at Ashton, who explained to investigators that he'd had enough. Becker pulled into the Misty Waters gas station, and Ashton got out to urinate.

Ashton then turned around, pulled out a gun and fired, the complaint alleged.

The suspect allegedly pulled Becker out of the vehicle and left the scene, court documents said. He then turned himself in.

Court documents said investigators found 10 spent shell casings from a Glock 26 handgun. Court records did not list an attorney for Ashton as of Monday.