A police corporal in Maryland was charged with second-degree murder on Tuesday in the fatal shooting of a suspect who had been handcuffed in the back of his patrol car the previous night, the authorities said.
The corporal, Michael Owen, a 10-year veteran of the Prince George’s Police Department, shot William H. Green Jr. seven times after a traffic stop on Monday night in Temple Hills, Md., on the outskirts of Washington, Henry P. Stawinski III, the county police chief, said Tuesday evening at a news conference.
Corporal Owen and another officer had been responding to a series of motor vehicle accidents in which Mr. Green, 43, had hit several cars and was suspected of being under the influence of an unknown substance, the chief said.
The officers had been waiting for another officer to arrive to evaluate Mr. Green for drugs when Corporal Owen opened fire, according to the chief, who said Mr. Green’s hands were cuffed behind his back at the time.
“I have concluded that what happened last night is a crime,” Chief Stawinski said. “There are no circumstances under which this outcome is acceptable.”
Corporal Owen was also charged with voluntary and involuntary manslaughter, first-degree assault and use of a firearm to commit a violent crime, said the authorities, who on Tuesday walked back an initial police account that witnesses told them a struggle had preceded the shooting.
“That was not corroborated,” Chief Stawinski said.
The shooting of Mr. Green, who lived in Southeast Washington and whose family said he worked for Megabus, drew condemnation from the American Civil Liberties Union. It also recalled previous fatal shootings by the police in Prince George’s County, where the majority of residents are black.
“There is no reason why a handcuffed person should ever be shot multiple times by a police officer, let alone shot multiple times inside a patrol car,” Deborah Jeon, the legal director for the American Civil Liberties Union of Maryland, said in a statement on Tuesday.
Mr. Green’s family said he was not a violent person.
“Since the day he was born he was the most gentle, sweetest, kindest,” Mr. Green’s cousin Juanita Sharma said in an interview on Tuesday. “He loved his mother and he loved his family,” she said. “He showed love to his family.”
Corporal Owen, who was placed on administrative leave, was taken into custody on Tuesday and is expected to appear in court for a bond hearing in the next few days. It was not immediately clear if he had a lawyer.
Prince George’s County officials said they were in the process of getting body cameras for police officers. Corporal Owen was not wearing one at the time of the shooting.
During the news conference on Tuesday, a local resident confronted county officials about police shootings.
“We understand you’re upset,” Angela D. Alsobrooks, the Prince George’s County executive, said. “We get it. I promise you we will not minimize it.”
Sheelagh McNeill contributed research.