SAVANNAH — The mother of a handcuffed man killed by police said Monday she doesn't believe investigators' findings that her son was armed with a gun, and she suspects a cover-up to protect the officer who shot him five times.

Charles Smith, 29, died minutes after Savannah-Chatham Metro Police arrested him Sept. 18 at a convenience store on warrants related to a stolen vehicle. A grand jury last week concluded that the shooting was justified, saying evidence showed Smith managed to move his cuffed hands to the front of his body after being placed into a patrol car and drew a gun that officers missed while patting him down.

Speaking to reporters at a roadside memorial where her son was shot, Penny Nelson said she still believes the officer who fired the shots, David Jannot, "needs some kind of punishment."

"I believe there was a cover-up somewhere down the line, all of them working together," Nelson said. "The way they said it happened, it couldn't have happened like that."

Chadrick Mance, an attorney for Smith's family, has filed notice with Savannah officials that he intends to file a wrongful death lawsuit seeking $3 million. But he said Monday he is not committed to filing a suit.

Mance also hedged when asked whether he's alleging police planted a gun on Smith's body.

"We wouldn't remove that possibility," Mance said. "We don't really know what happened that day."

Lab tests confirmed Smith's DNA in skin cells found on the grip and the ammunition clip of a 9 mm handgun found next to his body. He also had marijuana, cocaine and other drugs in his system. A little more than a year before he was killed, Smith had been released from a Georgia prison where he served less than two years of a five-year sentence for aggravated assault, cocaine possession, and possession of a firearm by a convicted felon.

Asked for comment, Savannah officials provided a copy of a response letter City Attorney Brooks Stillwell sent to Mance last week saying "an exhaustive review of the evidence" found that Smith had a gun.

Jannot's attorney, Doug Andrews, said Smith's mother and her attorney have shown no evidence police staged a cover-up.

"Mr. Smith was high on (drugs), was a three-time convicted felon in possession of a firearm and instead of dropping it when commanded, aimed it at the police," Andrews said. "Officer Jannot had the duty to protect the officers and any bystanders."