How to kill your father?

The video can only capture the height of 1.5m in order not to capture the knot that has been wrapped around my father's neck. After my father woke up in the secret room, his range of activities was limited and he couldn't get rid of the knot around his neck. He planned to open the door and call for help. The murderer saw a key with a saw blade, and the key was about to break. After his father picked up the key, he broke it with a little effort. The murderer put a complete key on the beam, half exposed, and guided his father to climb the ladder. When my father reached for the key, he pulled the rope, causing my father's center of gravity to be unstable and fall. The murderer observed all this from the window and recorded it on his mobile phone, then saved the edited video in his mobile phone and threw it in. There are two murderers here, one is the pig-headed man who tied the rope, and the other is Ning Hao who observed and guided everything.