A state prison guard has been arrested in a sting in which he allegedly agreed to smuggle drugs and cell phones to inmates in exchange for cash, Santa Clara County sheriff's officials said Wednesday.

Sergio Javier Noguera, 38, a guard at Salinas Valley State Prison in Soledad (Monterey County), was taken into custody about 10:30 p.m. Tuesday after he showed up for a meeting in Gilroy with undercover detectives pretending to be a source of contraband for inmates, said sheriff's Sgt. Rick Sung.

Noguera believed he would be paid $2,500 to smuggle in an ounce of methamphetamine, an ounce of heroin, 3 1/2 ounces of marijuana and four cell phones, authorities said.

The investigation began in April, when an informant told detectives that Noguera had been providing drugs and cell phones to inmates at the prison, which employs 946 guards and houses about 3,700 minimum- and maximum-security inmates.

Noguera is being held in lieu of $130,000 bail on drug-related counts, Sung said.

Noguera has been a guard at the prison for eight years. If he is released on bail, he will be reassigned to another position outside the prison while the investigation continues, said Sgt. Kim Traynham, a prison spokesman.