A Columbia Heights man was found guilty of first- and second-degree murder Tuesday in the killing of a man in a Minnetonka park-and-ride lot with a gun stolen from a police officer’s home.

Prosecutors contended that Marcus Hallmark used a black Ruger .380 handgun to fatally wound Thomas John Russ, 32, last March as the two changed a flat tire in a Metro Transit parking ramp off Interstate 394 at the Hopkins Crossroad interchange. On Tuesday the jury agreed, convicting Hallmark on both charges.

Hallmark, 26, of Columbia Heights, was being held in the Hennepin County jail and is set to be sentenced to life in prison without possibility of parole on Monday afternoon, the Hennepin County attorney’s office said.

The Hennepin County medical examiner determined that Russ died of two gunshot wounds to the head.

According to criminal complaints, Hallmark’s sister was Russ’ girlfriend. The three of them, along with another woman, had been hanging out March 3, the day of the shooting, at a home in Columbia Heights. One of the women lent her Ford Focus to Hallmark, and at some point Hallmark abandoned it at the park-and-ride ramp because it had a flat tire.

The four drove to the ramp, and the two women sat in the car while Hallmark and Russ fixed the flat tire. Around 11:15 p.m., both women reported hearing a loud bang and saw Russ on the ground. They then saw Hallmark bend over and fire another shot before running into the woods, the complaint states.

Police found Hallmark a few hours later in a swampy area near the lot. Investigators also found a handgun that had been reported stolen from a Hastings police officer’s home in Farmington. The serial number on the gun matched that of a gun stolen in Farmington.

Hallmark had previously been arrested in August 2010 in connection with a stabbing in Albert Lea, court records show. He also has been convicted four times since 2009 for committing or aiding and abetting burglary. He also has convictions for property damage, being a public nuisance, drug possession, theft, and aiding and abetting assault, court records show.