What does Mr. Aarons tell Jess is the cause of Leslie's death in "Bridge to Terabithia"?I want good and proper answers.

Mr. Aarons tells Jess that Leslie's body has been found "down in the creek".  Jess argues that Leslie could not have drowned, because "she could swim real good", but  Mr. Aarons explains that "that old rope you kids been swinging on broke", and that Leslie "musta hit her head on something when she fell".  Leslie then would have been dazed or unconscious when she fell into the swollen river, and thus would have drowne (Chapter 11).