CHATTANOOGA, Tenn. — An emotionally troubled 15-year-old died after falling from a window of a moving school bus, authorities said.

Rocky Joe Dockery, a Bradley County Schools student, reportedly climbed out one of the bus windows after the driver refused to drop him off closer to home than his regular stop.

The teen’s grandfather said he suffered from a bipolar disorder and was often teased by other students. He also said that Dockery’s adoptive father had died about a year-and-a-half earlier and that his adoptive mother is a nursing home resident.

Witnesses on the bus told investigators that Dockery was anxious to get to his grandparents’ house because he wanted to access the home computer before others. When the driver denied his request to get off early, the teen reportedly cursed and threatened to jump.

According to investigators, Dockery then “went to the third window on the passenger’s side of the bus, stuck one leg out the window and then the other. He was hanging onto the window with both hands from the outside of the bus, when he lost his grip and fell to the roadway.”

A police report said that the driver was in the process of stopping the bus when Dockery fell and ran to assist him until an ambulance arrived.

The teen reportedly struck his head on the road during the fall. He died the following day in a local hospital.