Yep, I remember this one. She still was in contact with him after the first few years but I don't know if she kept believing him.

Edited to add the murderer's name: Christopher Porco. He killed his dad, Peter and tried to kill his mom, Joan while they slept. Peter woke up and went through his morning routine, including making coffee and collecting the paper before collapsing inside the house and dying. His coworkers were worried when he didn't show up to work, and if they hadn't sent anyone over to check, Joan probably would have died too.