SAN DIEGO (Reuters) - An off-duty U.S. Border Patrol agent was arrested on Saturday in connection with the shooting death of a 27-year-old man at a Southern California home, police said.

Authorities have released few details about the shooting involving Border Patrol agent John Demery, but U.S. Customs and Border Protection said in a statement it had placed Demery on suspension and administrative leave pending developments in the police investigation.

Demery confronted Adam Thomas, 27, at a home in the community of East Hemet, about 75 miles (120 km) southeast of Los Angeles early on Saturday morning, and Thomas was shot following an argument between the two men, the Riverside County Sheriff's Department said in a statement.

Thomas, who had multiple gunshot wounds, was taken to a hospital where he was pronounced dead, Riverside County Sheriff's Department spokeswoman Deputy Patty Stoyer said.

Demery, 40, was arrested without incident on suspicion of homicide, the Sheriff's Department statement said. He was held in jail on $1 million bail and is due in court on Thursday, according to jail records.

Demery is a veteran U.S Border Patrol agent in the San Diego Sector, National Border Patrol Council spokesman Gabe Pacheco said.

"We are sad and shocked," Pacheco said. "We're waiting for more information from the investigation."

(Reporting by Marty Graham; Editing by Alex Dobuzinskis and Leslie Adler)