A grandmother in Georgia was allegedly killed by a stranger who followed her home and then choked her to death — crushing her neck with his knees and full body weight while she was lying on the ground, according to police and family members, who describe the murder as “horrific” and “mind-blowing.”

Hector David Sagastume Rivas, 21, is accused of murdering 52-year-old Camillia Williams sometime between 11 p.m. on March 12 and 1 a.m. on March 13, according to an arrest warrant obtained by Atlanta ABC affiliate WSB. Police in Cobb County say Sagastume Rivas strangled Williams and then dumped her body on the side of a road in a yard near her home in Marietta, where it was found last Thursday morning in a place that her family says left them shocked.

“When they found her in the bushes, we looked at the bushes real close and it just so happens to be a Camellia bush.” Camillia’s brother, Arsene Williams, told WSB. “It’s hard to believe that this is really truly happening,” he said. “I don’t know how to absorb it right now.”

According to Arsene and Williams’ family, the Louisiana native called a relative the night before her body was found and said she was being followed by a man who they claim was Sagastume Rivas.

“She didn’t know him,” said Tony Williams, another one of Camillia’s brothers. “The night before she was at the dollar store and she told one of my nieces the guy was following her,” Arsene alleged.

Cops say a motive has not been provided by the suspect yet, but he has admitted to allegedly killing Williams. He told investigators the details about using his knees, claiming he did so after trying to take her life with a chokehold, to no avail.

“I just can’t imagine what someone would have in their heart to do that to somebody,” Williams’ niece, Danielle Williams, told local NBC affiliate WXIA. “What he’d done was really horrific,” she said. “It’s mind-blowing.”

Sagastume Rivas was being held Wednesday on charges of felony murder. He’s been denied bond and is awaiting his next court date.

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