A Maryland police officer is facing a second-degree murder charge after allegedly shooting a man who was handcuffed behind his back and sitting in the front seat of a police car Monday.

Prince George’s County Police Chief Hank Stawinski announced murder, manslaughter, assault and weapons charges at a Tuesday press conference. Cpl. Michael Owen Jr., a 10-year force veteran, allegedly shot the man, William Green , 43, of Washington, D.C., seven times.

“I have concluded that what happened last night is a crime,” Stawinski said. There was no "reasonable explanation" for the events, he said.

The incident occurred in Temple Hills, a suburb of Washington, about 8 p.m. after police received a 911 call about a driver who struck multiple cars, said Christina Cotterman, a spokeswoman for Prince George's County Police Department.

Officers believed Green was under the influence of a substance and removed him from his car, according to a Tuesday police statement. While Owen and another officer waited for a drug recognition expert, they handcuffed Green and placed him in the front seat of Owen's police car.

"A short time later, for reasons that are now at the center of the investigation, Green was shot seven times by the officer’s duty weapon," the statement says.

Both officers administered medical aid to Green following the shooting, according to a statement. Green was taken to a hospital, where he died shortly after.

Cotterman said it was standard practice in the department for officers to place a suspect in the front passenger seat of a police vehicle.

A police statement says Owen's vehicle did not have a transport partition that would have allowed him to transport Green in the rear seat.

The case quickly drew criticism from the American Civil Liberties Union on Tuesday.

"Once again, a Black man – William Green – has been killed needlessly by officers with the Prince George’s County Police Department," reads a statement attributed to Deborah Jeon, the legal director for the ACLU of Maryland.

The statement criticized the police department for not having body cam footage of the incident and cited other incidents where black men were injured by Maryland police.

Authorities at a Tuesday press conference said they supported more police body cams and that this year's budget includes funding for all officers to have them.