Some more information has emerged in Shannon Fischer‘s presumed murder, according to this article. Earlier this month, her boyfriend confessed to strangling her. Now the motive has been made public: he thought she had stolen his drugs, specifically methamphetamine. He says he acted completely alone in the crime and told no one about it until four years later, when he walked into the police station and made his statement. No word yet as to why he chose to own up to it after all this time, when he could have gotten away with it.
Drug abuse takes another victim. Or four: Shannon, certainly; her boyfriend, who will spend the rest of his life in prison; and Shannon’s two children, who were both only babies when they lost their mother.
The Charley Project Blog 
Did you ever find out why he confessed? It sounds like there was not enough evidence to charge him with the crime and the only thing the cops have on him is the confession. Guilty conscience perhaps?
Guilty conscience is the only thing I can think of.