Natalie: Mr. Monk, look, his father kept a journal. He came back before he died.
Adrian Monk: Makes sense. It all makes sense now. His father died of a heart attack, like the coroner said. Paul must have found him. But he had a problem. His stepmother would inherit everything, and he would be completely cut out. Unless...
Natalie: She died too.
Adrian Monk: She not only had to die, she had to die first. Or at least it had to look like it. Because if she died second, even by a few minutes, her children would inherit everything. He got her to leave the house. "Come quickly. There's been an accident." He brought her up to Sweeney Road. And that's where he killed her. Then he set the stage. You were right about the phone call. There was no signal. He had to walk a few miles to call 911. Imitating his father was easy. Mrs. Claridge mentioned he sounded just like him. So it was perfect! They were both dead. And your stepmother had obviously died first.
Paul Buchanan: Who are you?
Natalie: This is my boss, Adrian Monk.