My father has had many jobs in his life. He's been a veterinarian, a meat processor (cross between butcher and slaughterhouse owner), a farmer, a power plant executive and a preacher. When he was running his meat processing plant, he used to do home deliveries to some of his customers.
One day, when I was about 7 or 8, he did a home delivery on his way home from the plant. He came in and got cleaned up. As we sat down for dinner, he started talking about the weird delivery he had just made.
The house he went to was owned by a young couple with a son about five years older than I was. When dad came by with the delivery, they invited him in. My dad's a really friendly guy, never meets a stranger, and never turns down an invitation to come in and chat, share a beer, etc.
Anyways, he's talking about the couple and their son. He remarks that the boy was really strange, but he chalked it up to the kid likely going through puberty. But he noted that he really thought it was weird that the parents never left the boy alone, anywhere in the house. If he went to his room, the mom got up and went with him, or his dad would stand just outside the door. The other thing he noted is that every door had a deadbolt on it, a deadbolt that needed a key to operate.
Every door. Closets, bathrooms, bedrooms. Every door.
Dad thought it was strange, strange enough that he brought it up to a friend who worked at DCFS, but nothing was ever done about it.
10 years pass, and the boy is a senior in high school. By all accounts he's a normal, quiet teen. Then one morning we turn on the news to see this normal, quiet teen had taken a double barrel shotgun and put a round into the back of both of his parent's skulls.