Two prison inmates are accused of hiding shanks in a cell wall and attacking rival gang members.

In charges filed Tuesday, Salt Lake County sheriff's deputies wrote that two Surenos gang members, 29 and 20, hid in the showers of the Oquirrh unit at the state prison in Draper on Aug. 5, then attacked a Nortenos gang member when he walked past them after a meeting with the Board of Pardons.

A fellow Norteno who rushed to the victim's aid also was attacked and suffered serious stab wounds to the front and back of his neck. He was flown to a hospital with life-threatening injuries.

None of the four prisoners would talk to investigators, deputies wrote, but the fight was recorded on a security camera.

Under the bunk area of the suspects' cell, investigators found a toothpaste-covered hole in the wall, deputies wrote. In the hiding place, they found a string attached to a 7-inch metal rod that had been sharpened on one end. They also found a second shank-like object.

The two prisoners are charged with transporting or possessing items prohibited in correctional facilities, a second-degree felony.

The 20-year-old suspect in 2007 pleaded guilty to aggravated assault and purchase or possession of a dangerous weapon; in 2008, he pleaded guilty to attempted escape from official custody.

The 28-year-old has a list of felony convictions dating back to 2001, when he pleaded guilty to attempted aggravated assault.