Before the cousins arrived, the culprit entered through the window and cut a small part of his skin leaving it on the floor. He then carefully placed a knife directly above the bed, placed in between the cracks of the ceiling. He did this for the other two rooms as well. When the cousins arrived, they locked the guestroom door, locked the window, and then laid down to sleep. The culprit climbed to the roof and knocking on the right parts, he dropped the knives from the ceiling directly onto the brothers below, killing them instantly.
Because you never specified how much of the culprit had to be in the room when the victims were killed.
Do you even wat