POWAY, Calif. -- A suspected illegal immigrant was in jail Tuesday, facing charges of sexually assaulting a 13-year-old boy on a secluded hillside in Poway after supplying him with alcohol, authorities reported.

Jesus Mora Nava, 30, allegedly met the victim in a canyon near Meadowbrook Middle School Monday and took him to a rural area west of the campus, sheriff's spokeswoman Jan Caldwell said.

The teen reported the alleged molestation about 3 p.m., according to Caldwell.

"Evidence was located at the scene," she said. "However, the (assailant) was gone. The evidence suggested the suspect had been spending nights at the scene."

Statements from the boy and from nearby merchants led investigators to identify Nava as the alleged attacker, and deputies launched a manhunt through the area.

The search continued past nightfall. Eventually, a helicopter crew using an infrared device located the suspect hiding near the scene of the alleged crime.

When Nava spotted deputies approaching on foot, he fled, but was captured after a brief chase.

The suspect was booked into county jail on suspicion of multiple child sex-assault charges, along with a federal immigration hold, Caldwell said.

He was held on $235,000 bail pending arraignment Thursday afternoon in downtown San Diego, according to jail officials.