A Prince George's County police officer who shot and killed a suspect who was handcuffed and wearing a seat belt inside a police cruiser Monday night in Maryland is in custody and facing charges, police said.

Cpl. Michael Owen Jr., a 10-year veteran of the department, is charged with second-degree murder, involuntary and voluntary manslaughter, first-degree assault and use of a firearm in the commission of a crime of violence, Prince George's County Police Chief Hank Stawinski said.

“I am unable to come to our community and offer you a reasonable explanation for the events that occurred last night,” Stawinski said Tuesday evening.

The officer who shot and killed a handcuffed suspect in custody is charged with murder. Prince George's County Bureau Chief Tracee Wilkins reports.

Police received a call about a traffic accident in the area of St. Barnabas Road and Winston Street in Temple Hills about 7:20 p.m. Monday, police said.

Witnesses told Owen and another officer that a man had struck their vehicles.

Officers found the suspected driver, 43-year-old William Howard Green of Southeast D.C., sleeping in his car nearby, police said.

The officers believe he was impaired, removed him from his car, handcuffed him behind his back and put him in the front passenger seat of Owen's cruiser while waiting for a drug recognition expert to arrive, police said. Owen got in the driver's seat next to Green.

Putting a suspect in the front of a cruiser that does not have a partition between the front and back seats allows the officer to maintain control of the suspect, Stawinski said.

A witness said he heard gunshots about 5-10 minutes later and went to the cruiser and saw Green still handcuffed in the passenger's seat and suffering from gunshot wounds, according to court documents.

A Prince George's County police officer charged with killing a suspect had fatally shot another man in 2011. News4's Darcy Spencer reports.

Owen fired his gun seven times, striking Green multiple times, according to court documents.

“Please tell me what could he have done to cause someone to draw a gun and fire, not once, multiple times?” Green's fiancée said. “Kill him on the spot.”

Officers then tried to save Green's life using their trauma kits, police said.

"I was told they performed CPR," Green's fiancee said. "I don't see any."

It is unclear if Green was buckled into the seat as police reported Monday night, Stawinski said, and PCP does not appear the cause of the erratic driving, as police reported the officers suspected.

Police said Monday night two witnesses said they heard a struggle coming from the cruiser and heard loud bangs, but the existence of those witnesses has not been supported by the investigation, Stawinski said.

A man told News4 Green was in the squad car for a while before shots were fired.

“Maybe 25, 30 minutes max,” he said.

Video obtained by News4 shows officers dragging Green out of the squad car with his hands still cuffed behind his back.

“They dragged him our and left him on the ground,” his fiancée said. “He’s still in handcuffs with his hands behind his back. They didn’t even have the decency to take the handcuffs off.”

The handcuffs were removed when paramedics arrived.

The officer did not have a body camera, police said.

In 2011, Owen fatally shot a man in Palmer Park. Police said Owen was leaving a Toys for Tots event at police headquarters when he saw Rodney Edwards lying in a grassy area on the side of Greenleaf Road. Police say Owen, who was in uniform, stopped to help Edwards, but Edwards pointed a gun at him. Owen shot him several times, police said.

Prince George's County State's Attorney Aisha Braveboy said in a statement Tuesday her office will conduct a “thorough and independent investigation.”

"We will seek truth and will vigorously pursue justice in a way that is fair and responsible," Braveboy said in the statement. "Once we have received all information and completed our own investigation and analysis, I assure you that my office will be transparent and accountable to the public about our findings and how we will move forward."

Deborah Jeon, legal director for the the American Civil Liberties Union of Maryland, said in statement Tuesday that there is no reason for an officer to shoot a handcuffed suspect multiple times inside a patrol car. Jeon called it “completely unacceptable” that Prince George's County's police department doesn't equip all its officers with body cameras.

“These deaths are completely preventable,” Jeon said. “Police characterize them as unavoidable, but they are not. And body camera footage will show that.”

“There is absolutely nothing about this incident that is acceptable,” County Executive Angela Alsobrooks said.

She ordered an independent review of department training methods and practices.

Green was a father of two who worked for Megabus and was due for a promotion Tuesday, his fiancee said.

“He mattered,” his fiancée said. “He was loved. And I don’t have him no more. I don’t have him no more, just like that.”