A Modesto man has died of a beating he received from two men who apparently mistook him for a sex offender, the police say.

Jace Decker, 63, was attacked on August 10 in Modesto’s Garrison Park. He died on Sunday, September 1.

Police have arrested Matthew Arguello, 21, and are seeking his alleged accomplice, Ruben Rosales, 25.

The two men reportedly believed that Decker — a homeless man who frequented the park — was a registered sex offender, Sacramento TV station KTXL reported. Decker was not a sex offender, and acquaintances of his from the park described him as a quiet man who had never recovered from the death of his wife.

After the beating, Decker reportedly declined medical treatment, but police officers were called back to the park barely an hour later when he fell unconscious. He remained in a coma for three weeks before his death, KTXL said.

Arguello was arrested August 16 and charged with attempted murder. He is scheduled to appear in Stanislaus County Superior Court on Thursday.

Rosales remains at large.