A Utah man accused of two Los Angeles-area shootings that killed an off-duty deputy and a Russian athlete in June pleaded not guilty in court on Monday.

Prosecutors had charged 30-year-old Rhett Mckenzie Nelson of two counts murder, two counts of second-degree robbery and one count of attempted murder in connection with the killings and two robberies on June 10.

Nelson, who was reported missing out of St. George, Utah weeks before, allegedly gunned down Dmitry Koltsov from his vehicle in an unprovoked attack in downtown Los Angeles.

About an hour later, Nelson walked into a Jack in the Box in Alhambra and shot Los Angeles County sheriff’s Deputy Joseph Solano in the back of the head as the officer stood by the counter, according to investigators.

Nelson then went to Long Beach and robbed a Shell gas station and a 7-Eleven store, the L.A. County District Attorney’s Office said. Authorities found him in Long Beach the next day and took him into custody.

Before he left Utah, Nelson told his family he wanted to “make it on his own or die,” St. George Police Department Capt. Mike Giles previously said. Family members had been concerned that he was possibly suffering from drug and mental health problems but did not believe he was dangerous, according to officials.

Koltsov, a snowboarder from Russia, was 31 years old. Solano, 50, worked for the Sheriff’s Department for 13 years.

Nelson could face a maximum sentence of death or life in prison without parole if convicted as charged. He’s being held at the Twin Towers Correctional Facility without bail, inmate records show.

He’s scheduled to return to court on Sept. 6.