Scott Guy, His Parents' Story of Love, Betrayal, Murder and Courage by Tony Farrington contains excerpts from Mrs Guy's journal from the day her son was killed. It also contains details about the family that the couple have never shared before - including the letter from their former son-in-law.
"Since his arrest, Ewen has not contacted them to apologise for the hurt and trouble he caused the family," Farrington wrote. "They did receive one letter, which they considered weird, in which he wrote about how he spent his days in prison. He suggested that when he was released they might get back together and sit down and have a few laughs.
"They thought its contents were totally inappropriate and passed it on to police."
Police confirmed this week they had the letter and it had been added to their investigation file. The file remains open and police have said despite the verdict, they are not looking for anyone else in connection with Scott Guy's death.
The book reveals the tension between the Guy and Macdonald families, revealed through Anna and Ewen's 5-year-old daughter Lucy, who told her grandmother, Marlene Macdonald, that she had spoken to "hundreds" of people who said her father was innocent.
"But Granny Jo thinks he did it," she said. Mrs Guy told the author she was horrified to hear this, believing she had not given any indication of her feelings to her grandchildren.
The couple have differing opinions on what should happen next in the hunt for Scott's killer.
" They both agree that the court's decision has left a tangle of loose ends in their lives. Bryan refuses to dwell on this. Jo, on the other hand is not so disciplined," Farrington wrote.
The Guys speak for the first time about spending time with their dead son.
"They brought Scott home and laid him at rest in the office in their house. They were surprised at Ewen's reluctance to sit alone with his brother-in-law. He only entered the room when Anna insisted he say goodbye to Scott. Bryan and Jo stole moments with their son as often as they could. 'What did you see Scotty?' Jo asked. 'You must have seen something. Who did this terrible thing?' Farrington wrote.
Mrs Guy also speaks of being torn over how much to help her daughter.
"Anna didn't choose this life. We certainly didn't," she wrote in her journal. "A good thing to remember is that we weren't made for having children in old age. I'll have to be careful not to do too much ... I don't want our lives to be ruled by helping Anna. She is 30 - she's got to find her own way. So do Nikki and Callum. I feel very aware that I don't have the energy to do everything every day. I want to be a grandmother who listens, loves and does fun things."
