But when Rettig took the stand on Jan. 17, 2013, he refused to answer questions about the events that led to Mortensen's death on Nov. 16, 2009.
Last July, Rettig was charged in 4th District Court with second-degree felony obstruction of justice. Last week, he accepted a plea deal and pleaded guilty to a reduced third-degree felony count of obstruction of justice.
According to a probable cause statement filed in court, investigators met with Rettig at the Utah State Prison in December 2012, and he agreed to testify. But after being put on the witness stand twice in two days during Bond's trial, he refused to testify, even after being ordered to do so by Judge Thomas Low.
After William Barrett accepted Rettig's guilty plea last week, he immediately ordered Rettig to serve a zero to five years in prison but ordered the sentence to run concurrently to the prison sentence he is already serving.
Meanwhile, Rettig is trying to appeal his 25-years-to-life sentence, claiming that he was not advised of his right to appeal the sentence before the time limit for an appeal expired.
Rettig is asking to appeal only his sentencing, so if he wins the appeal, it will not change his plea, but rather result in him being re-sentenced. But if he is re-sentenced, prosecutors could ask for a sentence of life without the possibility of parole, since Rettig failed to hold up his end of the plea agreement by refusomg to testify.
Last January, a jury found Bond, 26, guilty of aggravated murder, three counts of aggravated kidnapping and one count each of aggravated burglary and aggravated robbery. Low sentenced Bond to life in prison without the possibility of parole.
According to court documents, Rettig and Bond broke into Mortensen's Payson Canyon home the night of Nov. 16, 2009, to steal the man's extensive gun collection. During the burglary, Rettig trained a handgun on Mortensen as Bond slashed the 70-year-old man's throat with a knife, prosecutors said.
Rettig also helped tie up Mortensen's son and daughter-in-law, Roger and Pamela Mortensen, who happened to come to the house during the burglary.
The couple spent roughly eight months in jail facing murder charges for the slaying before a tipster led police to Bond and Rettig.