The whole motive behind the murder was evidence of Tina Trexler's negligence that Ron intended to use at the upcoming custody hearing.  People what to say how bad Ron was and all that controversy came from an episode of Court Tv's The Investigators-Tangled Web.  He did have some steroid induced anger problems and while married to Tina she was an alcoholic and a drug addict that liked to party. She divorced him when he started to get himself straight and did not what himself or their daughter Kierstyn around. It caused a lot of stress on the marriage and after the divorce she kept up her lifestyle that was what caused the ruling to go to Ron. Then when Ann got involved she wanted to raise Kierstyn and Ron let Tina and Ann have the split custody of her until his job was taking him out of state to Montana. He had photos of Tina drinking and doing drugs on the beach at the time she had custody of Kierstyn. Ann was the one that had Kierstyn during Tina's time for custody because Tina was to busy partying to want anything to do with her daughter. Ann knew that if there was a custody hearing they would loose because of Tina's life style and the fact that Ron had got his life straight and had witnesses that would testify for him he was happy and life was going his way. That's why Ann had him killed because she couldn't allow him to expose the truth about Tina.