Watch closely as the detective is pulling into the "parking lot" of the Bates motel for the second time to sneak into Norman's house to see his mother. Stop reading if you haven't seen the movie, and wish to do so, or it will ruin the movie. You can see in the background that Norman is taking linens to a room near 10. He enters the room before the detective gets out of his car.
When the detective goes up to the house, Norman's "mother"(which you need to know from the end of the movie that Norman is his mother)comes from upstairs to kill the detective. Can Norman teleport or something?