Authorities said the cause of death for a homeless man killed Wednesday evening was strangulation.
The killing happened at a homeless encampment along the Concord/Pleasant Hill border.
Authorities said they arrested 38-year-old James Riley near the homeless camp at the Interstate 680 overpass at Concord Avenue.
The victim has been identified as 47-year-old Jerald Nagle, said Sheriff's spokesman Jimmy Lee.
Riley and Nagle had reportedly gotten into a fight. Lee said both men are transients.
Riley was booked at County Jail in Martinez on homicide charges. He's being held on $1 million bail.
Sheriff's officials are continuing their investigation.
Concord Patch will provide updates on the story as soon as they become available.