what happened to leslie in bridge to terabithia

In "Bridge to Terabithia," Leslie dies while trying to swing her way into Terabithia alone. The rope snaps, leaving her to drown in the stream below. Jess believes that its his fault that Leslie died because he didnt invite her along on the day trip with Mrs. Edmunds. There is a fan theory that Leslies death wasnt accidental, but rather suicide. The theory suggests that Leslie was depressed and self-harming, and that she had been bullied in the past. However, this theory is not supported by any official sources and is purely speculative.