MEMPHIS -- A fugitive suspected of fatally shooting a Memphis police officer was on federal parole at the time of the killing, according to federal probation officials, and the marijuana found in the car he was riding in may have constituted a violation of his parole.

Twenty-nine-year-old Tremaine Wilbourn faces a first-degree murder charge in the death of Officer Sean Bolton, 33, Memphis Police Director Toney Armstrong said at a Sunday news conference. Police say Wilbourn was a passenger in a 2002 Mercedes Benz that was parked illegally in a southeast Memphis neighborhood Saturday night.

They say when Bolton approached the car, Wilbourn got out of the car and confronted the officer, shooting him multiple times before fleeing.

Get Breaking News Delivered to Your Inbox

Bolton died at the hospital. The manhunt for Wilbourn continues.

CBS affiliate WREG reports that Wilbourn held up a bank in Covington, Tenn. in 2005, when he was 19. He was reportedly arrested by a special FBI task force and a judge sentenced him to 10 years in federal prison.

Wilbourn was reportedly released July 1, 2014, just over a year before Bolton's fatal shooting. He was on federal probation, and the conditions of his supervised release included that he couldn't associate with known criminals or violate a local, state or federal law, according to Dan Kilgore, the chief U.S. probation officer for the western district of Tennessee.

It also forbid him to use or be around drugs, reports WREG.

Bolton reportedly may have caught him violating those terms before he was shot. Armstrong said Bolton interrupted a drug deal in progress, and officers found about 1.7 grams of marijuana in the car.

The amount would typically result in a misdemeanor citation and a fine, police have said, but because it may have also constituted a parole violation, it would have also required federal probation officers to notify the court system, Kilgore told Crimesider.

That could have resulted in a hearing to determine his overall compliance with his release conditions, Kilgore said.

Kilgore said federal probation officials have already filed a violation petition with the court based on the murder charge.

Armstrong said Bolton saw the illegally parked car and shined his squad car's spotlight on the vehicle.

Bolton got out of his car and walked toward the Mercedes, Armstrong said. Wilbourn got out of the Mercedes, confronted Bolton, and they got into a physical struggle, Armstrong said.

Wilbourn took out a gun and fired, striking Bolton multiple times, Armstrong said.

A civilian used the officer's radio to notify police about the shooting, according to Armstrong.

The driver of the vehicle Bolton was in turned himself in to police, and police had described him as a person of interest before he was released without charges.

Bolton was white, and Wilbourn is black. Armstrong said at Sunday's news conference that the community lost a great man and dedicated servant.

"We as a community must come together and remember that all lives matter. Not just black lives. Not just white lives. But all lives matter," said Armstrong, who is black.

Bolton was a Marine who served a tour of duty in Iraq, police said. He joined the department in 2010.

The U.S. Marshal's office is issuing a $10,000 reward for Wilbourn's arrest. He's considered armed and dangerous.