Officials realised Porfirio Duarte-Herrera was missing during a morning head count at Southern Desert Correctional Centre near Las Vegas, and a state Department of Corrections statement said search teams were looking for him.
Duarte-Herrera, from Nicaragua, was convicted in 2010 of killing a hot dog stand vendor using a motion-activated bomb in a coffee cup atop a car parked at the Luxor hotel-casino.
Records show his co-defendant, Omar Rueda-Denvers, remained in custody on Tuesday.
The 47-year-old from Guatemala is serving a life sentence at a different Nevada prison for murder, attempted murder, explosives and other charges.
A Clark County District Court jury spared both men from the death penalty in the slaying of Willebaldo Dorantes Antonio, whom prosecutors identified as the boyfriend of Rueda-Denvers’ ex-girlfriend.
‘Mystery’ photos still unexplained
Prosecutors said jealousy was the motive for the attack on the top deck of a two-storey parking structure.
The blast initially raised fears of a terrorist attack on the Strip.
Officials described Duarte-Herrera as 5 feet, 4 inches tall (162cm) and 135 pounds (61kg), with brown eyes and brown hair.
