A childhood belief about ghosts

In middle school my spanish teacher told my class about a worker who has fallen from a ladder in the gym and had broken his neck and died. She said that weird things would happen the year before when she was a coach, like doors that were locked were unlocked the next morning and vise versa. Or when they got there in the morning the music in their office or the showers in the locker rooms would be on. She also said that one girl said that she heard someone whisper in her ear when she was changing in the locker room. Now one of my classmates, lets call her.... bob was really jumpy about this. She was in my P.E. class too. She told our coach about it but she said that it wasn't true. One day when we were changing back into our normal clothes, we were the only one in the locker room because everyone else was in the hallway. Then the lights went out and it was pitch black causing bob to scream because she thought it was the ghost and cause me to scream because she screamed. We ran out of the locker room only to find out that it was our coach playing a trick on us. But I'm still a little wary every time i go in there.