Fallen Angels (2002)

Nell "Freaky" Fisher is targeted by the popular girls at school and sleeps in the dorms basement.  She has been an outcast since she reported popular, dreamy Professor Layton's attempted sexual assault.  All the students loved Layton and since he's been fired, they blame Nell.

When Layton attacks Nell in the basement, a fire breaks out. Layton ends up locked inside the basement  and it explodes.  This is why you should never have lit candles and gasoline in the same room.

Years later, a filmmaker doing a documentary on the story gets the girls back together for a visit to the school.  Unknown to them, he  plans on having them stay overnight in the school.  None of them are happy about it, but they aren't as angry as the town folk who don't want to revisit such a bad memory.

Soon strange things are happening and people are dying.  Is it the townies?  The ghost of Layton?  Someone else?  It's just like being right back in high school and everyone still hates Nell. Yikes.