So the dog, which was put on a chain, would trust their daughter's ex-boyfriend enought to let him him, or A, put him there? And neither of your parents would think twice about him being there, either? And he would have full access to the house. etc. Would they both know your parents Thursday night routines as well as you did?
Sounds like after the murder, A's living conditions improved greatly. She got the house. Did she get the renovations done that she told the newspaper she was getting done "making their dreams her dreams?"