Wind in the Box: The Elevator Ghost

To investigate a murder in a residential neighborhood, the police retrieved the elevator surveillance footage from the scene and discovered a paranormal event:

At the time of the victim's death, the empty elevator made several trips, as though controlled by an invisible person, traveling between the first floor and the crime scene...

What was the truth?

The first story in a series. It's a standalone case, so enjoy without worry~

Daily updates, complete within ten days.

Theme: Before a box is opened, no one knows where the wind inside it is coming from