Authorities are looking for 24-year-old Steven Gallagher. He escaped Tuesday, along with 23-year-old Jonathan Mundo.
Sheriff's officials say Mundo was located early Wednesday morning in Highland and taken into custody. He is being held without bail.
Twenty-year-old Kenneth Gillis, who is suspected of driving the two inmates from the area after the escape, was also arrested on Wednesday.
Gallagher is still at large. He's accused of robbery, conspiracy and assault with a deadly weapon.
Anyone with information regarding Gallagher's whereabouts is urged to contact the Sheriff's Valley Dispatch Center at (909)387-8313. Those wishing to remain anonymous can call the We-Tip Hotline at 1-800-782-7463 or www.wetip.com.