A friend of the victim has told The Salt Lake Tribune that Flores and Rivera left California for Utah on May 7, 2011, because Rivera promised Flores a construction job. Prosecutors said the two men got into a fight inside Rivera's vehicle two days later, and Rivera stabbed Flores in the chest.
Flores' body was found in February 2012, when police received a tip directing them to a home at 3812 W. 4550 South, in Roy. On Feb. 9, 2012, after three days of digging, police found Flores' body under three to four feet of earth in the backyard of the home.
After Flores' body was found, the homeowner, Sarah Munn, was charged with obstruction of justice for allegedly lying to police.
Rivera was charged in September and pleaded guilty about two weeks after he was charged. Defense attorney Camille Neider has said it was an Alford plea that is, Rivera does not admit guilt, but he believes prosecutors could likely prove the charges to a jury. Rivera maintains he killed Flores in self-defense, Nieder said.
Court documents in Munn's case indicate Rivera required 35 stitches for a cut to his face on May 9, 2011. Munn initially told police that Rivera who lived at the Roy home part-time and is the father of three of Munn's children had been injured during a road rage incident, then later told police that she caused the cut herself.
Two days later, Rivera rented a tractor and dug a hole in Munn's backyard, police wrote. Munn said the equipment was used to dig a hole for an in-ground trampoline, but the hole later was filled because it was the wrong size, police wrote.
Flores' body was found in the same area where the hole had been dug, according to the probable cause statement.
Munn pleaded guilty in a separate drug case, and the obstruction of justice charge was dismissed.
Rivera, who has prior convictions for drug distribution and escape from custody, resides at the Utah State Prison in Gunnison.