PHOENIX — NIX - Police using helicopters and search dogs hunted Saturday for three convicted murders who escaped from a northwest Arizona prison.

Two of the escapees, accompanied by a woman, later hijacked a semitrailer at gunpoint, the Mohave County sheriff's office said.

The three inmates were discovered missing Friday night from the Arizona State Prison in Golden Valley. A Department of Corrections spokesman said the men escaped by cutting a hole through a perimeter fence.

They were identified as: Tracy Alan Province, 42, who was serving a life sentence for first-degree murder and robbery; Daniel Kelly Renwick, 36, who was serving 22 years for second-degree murder; and John Charles McClusky, 45, who was serving 15 years for second-degree murder, aggravated assault and discharge of a firearm.

According to authorities, two of the inmates, along with a woman identified by Flagstaff Police as Casslyn Mae Welch, hijacked an 18-wheeler occupied by two men on Interstate 40 outside Kingman early Saturday morning.  Officials say the prisoners were armed with handguns.

The truck drivers were released at a Flagstaff truck stop around 5 a.m. and the suspects fled, the sheriff's office said.

The escapees were last seen wearing orange prison jumpsuits.