A Nevada jury hoped sending Troy Michael Kell to prison for the rest of his life would prevent him from ever killing again.

But Tuesday morning Kell and three other inmates were charged with aggravated murder in the stabbing death of Lonnie Black-mon July 6. If convicted, the four could face the death penalty.Kell, 26, Eric Thomas Daniels, 24, John Fredrick Cannistraci, 25 and Paul Richard Payne, 20, are accused of stabbing Blackmon to death in a hallway of the Central Utah Correctional Facility in Gunnison. They'll be arraigned at the prison Wednesday, July 27.

Blackmon, Kell and another inmate were being escorted in handcuffs to the prison's infirmary by an unarmed correctional officer. Details about the slaying are unclear as officials refuse to release the initial police report or details about the slaying because they fear prejudicing potential jurors.

It is known that someone forged a medical request slip for Blackmon, and when an officer came to take him to the infirmary, he didn't question it. As the three men made their way to the infirmary, investigators believe someone may have slipped Kell a home-fashioned knife, referred to by inmates as a shank, and key to the handcuffs.

Kell allegedly unlocked his right hand and began swinging the shank at Blackmon. As the officer ran to get help, Blackmon and the two men struggled. They apparently pushed him up against bars of a shower area where two men in the shower grabbed Blackmon while one man stabbed him numerous times.

Officers in a control room saw the fight and called the SWAT team. They responded in minutes, but Blackmon was already dead. Kell is accused of doing the stabbing, but it is unclear what role the other four men played.

Kell, Payne and Daniels were moved to the Draper prison's maximum security facility shortly after the slaying. Cannistraci is still in Gunnison in the infirmary.

Kell was one of several teenagers convicted of luring a man into the Nevada desert and then shooting and robbing him in 1986. The murder was dubbed the"Show-and-Tell" murder because the teens took several people to see the body. He was sentenced to life without the possibility of parole. Corrections spokesman Jack Ford said he wasn't sure why Nevada officials sent Kell to Utah.

Cannistraci was serving time for attempted aggravated robbery and drug convictions out of Washington County. Daniels was serving time for two forgery convictions out of Salt Lake County. Payne was serving a life sentence for aggravated robbery, kidnaping, escape and a number of other con-victions out of Carbon County.

Officials originally said the suspects were known white supremacists and stabbed Blackmon because he was black. They are now backing away from racism as a motive for the slaying, saying it is more likely that Kell and Black-mon were involved in an ongoing dispute, Ford said.

An argument erupted between the two men during a recreational activity, and the stabbing could have something to do with that, he said.

Payne and Daniels were two of the ringleaders in last summer's near-riot in the Gunnison prison, Ford said. The uprising, which caused $37,000 damage to the prison, started when correctional officers found a weapon similar to the one used to kill Blackmon in an inmate's cell.