COLLEGE PARK, Md. — A Maryland county has agreed to a $20 million settlement with the family of a man who was handcuffed in a patrol car when a police officer shot and killed him, a county official said Monday.

The Prince George’s County police officer who killed William Green in January was arrested on charges including second-degree murder and has a trial scheduled for next year.

Michael Owen Jr., who was a 10-year veteran of the police department, has been jailed since his arrest.

Green, 43, of Washington, D.C., was unarmed with his hands cuffed behind his back when Owen shot him six times, County Executive Angela Alsobrooks said during a news conference Monday. She noted that Owen was the first police officer in the county’s history to be charged with murder for a killing while on duty.

“I am deeply sorry for your loss,” Alsobrooks told Green’s mother, who was joined at the news conference by Green’s adult daughter and son.

Investigators didn’t find any evidence of a fight between Owen and Green before the officer fatally shot him on Jan. 27, a police report said.

That finding contradicted statements on the night of the shooting by a police department spokeswoman, who told reporters that two “independent witnesses” said they saw or heard a struggle “of some sort” coming from the patrol car before they heard loud bangs.

Owen fired seven shots at Green and struck him multiple times, according to the police report.

Owen had handcuffed Green behind his back after responding to a traffic accident and finding him sleeping in his vehicle, apparently under the influence of an unknown substance, the report said.

Owen then put Green in the front passenger seat of the patrol car, which did not have a partition between the front and back seats. Officers are permitted to transport arrested suspects in the front when their patrol cars lack partitions, police said.

A prosecutor, Renee Joy, said in January that Green complied with officers’ commands when he was taken out of the car and handcuffed. Joy said Green posed “absolutely no threat.” Investigators did not find any weapons in Green’s possession or in his vehicle.

During a news conference shortly after Green’s shooting, police department spokeswoman Christina Cotterman said two witnesses told police they either saw or heard a struggle before the shooting. Cotterman also said officers smelled PCP and believed the man was under the influence of that drug. However, the county’s police chief later said PCP did not appear to have been involved and that no account of a struggle in the cruiser could be corroborated.

The shooting wasn’t caught on body-camera video because the officer didn’t have one, police said.

Owen’s trial is scheduled to start on March 22, 2021.

Prince George’s County has nearly 1 million residents and its police department is Maryland’s fourth largest law-enforcement agency, with more than 1,500 officers covering a wide swath of the Washington, D.C., suburbs.

Earlier this month, The Washington Post reported that the police department’s early-warning system flagged Owen months before he shot Green. Owen triggered the system by using force twice in quick succession last summer, but his supervisors hadn’t been formally notified until January and didn’t act before Owen killed Green, the newspaper reported.

Owen was involved in at least two other shootings. In 2011, he fatally shot a man who pointed a gun at him after Owen left an event at police headquarters, the department said. Owen was placed on administrative leave after that killing.

In 2009, Owen was off-duty when someone tried to rob him outside his home, the Post reported. Police officials said the would-be robber fired, but Owen was not hit and returned fire. The assailant fled, according to police.

The Associated Press contributed to this report.