Bond's attorneys said they plan to file an appeal based on issues with his co-defendant's testimony.
As part of his plea deal, Bond agreed to be sentenced to life without the possibility of parole if found guilty of aggravated murder. Though he already knows his sentence, Bond will be formerly sentenced on March 5, when Mortensen's family will be able to address the court.
"I don't feel victorious," Mortensen's wife, Darla Mortensen, told reporters after the verdict was read. "I'm happy that it's over … I feel like it's such a tragedy … I'm grateful that the truth has come out."
Mortensen's daughter-in-law, Pamela Mortensen, called the guilty verdict "a long time coming."
Pamela Mortensen and her husband, Roger Mortensen, were originally charged with the professor's murder, and were held in jail for five months before Bond's ex-wife tipped police.
"Due to false charges, family and friends turned on us," she said outside of court. "We are finally glad that the truth has come out that Roger and I were victims in this crime."
During closing arguments in 4th District Court, Bond's attorneys claimed he should be acquitted of aggravated murder because he was coerced to kill the 70-year-old man by confessed accomplice Benjamin David Rettig.
The defense pointed to notes written by Bond to another inmate while at the Utah County Jail.
The 21-year-old inmate testified that while the two were held in the jail in 2011, he and Bond would write notes called kites and pass them using what the inmate referred to as fishing tying the notes to a shoelace and tossing them between cells.
One night, the inmate wrote a note asking why Bond was blaming Rettig for killing Mortensen by cutting his throat and stabbing him in the neck at the victim's Payson Canyon home in 2009.
In a neat cursive, Bond responded.
On Friday, Detective Zach Adams read the notes aloud during Bond's third day of trial.
"Well, Ben made the situation," the note read. "When Kay and I tried to talk to him, he freaked out more and a bunch of other s*** happened. It came to the point where he was going to kill him, but made me instead … It was that or he said he'll shoot me so that no one could say anything. That's why his throat was cut, he wouldn't give me the gun. I thought he was suffering, so that's why I stabbed him."
A Utah County Jail staff member has testified that Bond and the other inmate had stayed in nearby cells, and a handwriting expert with the Salt Lake County Police Department verified that the notes were in Bond's handwriting.
Deputy Utah County Attorney Tim Taylor told the jury that it was Bond, not Rettig, who killed the professor.
And he did it willingly and was never threatened, Taylor said.
"Why did he kill Kay Mortensen?" Taylor said. "Because Kay knew him. Kay knew this man. Kay didn't know Ben Rettig … There's a motive for killing Kay. He knew exactly who he was."
Taylor called Bond's jail note a "self-serving statement," but Bond's attorney, Bautista, maintained in his closing argument that Bond felt his life was threatened and that he was forced to kill his old friend.
"The truth of what really happened is, as Martin said in his notes, that he had to kill a friend ... to save his own ass," Bautista said.
Edward Leis, with the state's medical examiner office, testified Friday that Mortensen had at least five slashing injuries on his neck. He also had a single stab wound on the back of his neck.
Leis testified that it likely would have taken Mortensen anywhere from one to five minutes to die from his wounds.
"It's not going to be immediately fatal," Leis said. "It's not going to render him unconscious immediately either."
Utah County prosecutors claim Bond and Rettig, 25, killed Mortensen the night of Nov. 16, 2009, so they could steal his guns.
Mortensen's wife, Darla Mortensen, took the stand Friday and said her husband had loved guns since he was a child.
"He just had a passion for guns," she testified. "From the time he was a young boy, he was exposed to guns and learned to love them. It was something he was around his whole life."
But the victim's extensive gun collection was allegedly what prompted Bond and Rettig to kill the retired engineering professor.
Rettig who is serving 25 years to life in prison pleaded guilty in 2011 to aggravated murder and aggravated kidnapping for his part in the slaying. As part of his plea deal, Rettig had agreed to testify against Bond.
On Thursday, Rettig refused to follow through, but prosecutors put him back on the witness stand Friday morning after granting him immunity.
However, the immunity does not reach as far as federal charges, and at the advice of his attorney, Rettig invoked his Fifth Amendment right against self-incrimination.
Deputy Utah County Attorney Tim Taylor asked Rettig a series of leading questions that he did answer "yes" to, including that he was hesitant to testify because he did not want to be labeled a "snitch," at the prison, and that he was fearful of Bond.
Bond's attorneys, Stephen Howard and Bautista, raised several legal issues concerning Rettig's testimony and went so far as to ask Judge Thomas Low for a mistrial, but Low refused to grant the request.
Bautista said outside of court that those issues may have affected Bond's right to a fair trial. He said they will either file an appeal and will try to get another trial or have the charges dismissed.
Roger and Pamela Mortensen stumbled into the middle of the burglary/homicide when they showed up with a pecan pie for Kay Mortensen.
Pamela Mortensen has testified that they were tied up by Bond and Rettig but freed themselves and called police after finding Kay Mortensen dead in an upstairs bathroom.
Police initially did not believe their story. The couple were charged with murder and spent five months in jail before Bond's former wife went to the police with information about his alleged involvement. Guns owned by the victim were later found where Bond allegedly buried them near Vernal.
Taylor said after the verdict was read that an attentive jury was key to this case. He said he was glad that Mortensen's family can now have closure that the right person has been convicted for the murder.
"We feel bad [about Pamela and Roger Mortensen's arrests]," he said. "But in the long run, things turned out OK."