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The sister of the man accused of gunning down a Memphis police officer claims her brother "was defending himself."

Tremaine Wilbourn, 29, was being held on $9 million bond on Tuesday on first-degree murder charges for the fatal shooting of Memphis cop Sean Bolton, 33, according to court documents.

Wilbourn's sister, Callie Watkins, said her brother was acting in self-defense when he shot Bolton multiple times on Saturday night.

"Tremaine ain't no bad person," Watkins said. "He was defending himself."

"You know how they do, just trying to do you in," said Watkins, apparently referring to police.

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Memphis police have said that Bolton interrupted a drug transaction when he approached a car that Wilbourn was in, and investigators found 1.7 grams of marijuana and digital scales in the car.

A nearly two-day manhunt for Wilbourn concluded Monday evening when he turned himself into U.S. Marshals, who were offering $10,000 reward for information leading to his arrest.

The Memphis Police Department said Wilbourn was on supervised release after serving time for a bank robbery, and he was considered armed and dangerous.

Watkins told NBC affiliate WMC that the family "was just really worried about him" during the two days he was on the run.

"We knew it weren’t going to end pretty if he would have fought it out, so I’m just glad that he turned himself in," she said.

"He ain’t a coward," Watkins said.

Amid the manhunt, Memphis Police Department Director Toney Armstrong held up a picture of Wilbourn and stated: "You are looking at a coward, who gunned down a police officer over less than two grams of marijuana."

Wilbourn told Armstrong after his capture that he wanted the police director to know that he wasn't a cold-blooded killer and he wasn't a coward, Armstrong said during a Monday night news conference.

A funeral for Bolton, a five-year veteran of the force and a Marine Corps veteran, will be held Thursday.