A neighbor reportedly witnessed Chastain, who was randomly walking through the neighborhood, and called authorities, worried Chastain would harm an elderly man inside the home, James Raleigh. Raleigh allegedly exited his home to "investigate the commotion," and Chastain assaulted him.
Chastain fled the scene on foot but was located and taken into custody without incident, the Sheriff’s Office said.
Deputies interviewed the victim, and as they did, he collapsed on the ground and had issues breathing. Raleigh was reportedly transported to the hospital, where he was pronounced dead.
The Sheriff’s Office called the attack "unprovoked and senseless."
Raleigh was booked into the Sacramento County Jail for one count of homicide and remains held without bail, the Sheriff’s Office said.
In a statement obtained by KCRA-TV, Sacramento County Supervisor Rich Desmond said, "The number of unhoused on our streets has become a direct threat to our ability to create thriving, secure and peaceful neighborhoods throughout the County."