Updated

An inmate was convicted Thursday of murdering his cellmate by a jury that viewed gruesome videotape of the killer holding up his victim's entrails as he taunted guards from his bloody cell.

The same federal jury will decide whether William Sablan should be executed in the trial's penalty phase, which is to begin Monday.

Prosecutors say Sablan, 42, and his 37-year-old cousin, Rudy Sablan, killed Joey Jesus Estrella in 1999, after a night of drinking and fighting in the cell they shared at the federal penitentiary in Florence. Rudy Sablan's trial date has not been set.

Prosecutors said Rudy Sablan strangled Estrella with a headphone cord and that William Sablan used a prison-issue disposable razor to slash Estrella's neck. An autopsy showed Estrella, 33, bled to death and that some of his organs were removed after he died.

Early in the trial, prosecutors showed jurors a videotape shot by prison guards in which William Sablan is seen holding up Estrella's internal organs and making obscene gestures. Blood flowed under the cell door, and an "S" had been written in blood on the cell wall.

William Sablan showed no reaction to the verdict, which came after two days of jury deliberations. His attorneys declined to comment outside the courtroom.

U.S. Attorney Troy Eid called it "an extremely hard case" but said the outcome was just. He said Sablan would face life in prison if the jury votes against the death penalty.

William Sablan has a more than 20-year history of violent crime. Defense attorneys argued that he suffers from mental illness, brain injuries and post-traumatic stress disorder that left him unable to control his impulses.

Defense attorney Nathan Chambers blamed prison guards for lapses that allowed the inmates access to homemade wine, for placing three men in a cell designed for two and for failing to respond when an alarm button was pushed in the cell.