Did Neville Kill Voldemort?

Finally it is Neville who kills Voldemort in the films, as Harry and Voldemort duel Neville kills the snake and before the colliding magic ends Voldemort already starts to flake, Harry then hits him with a disarm spell, but not a killing curse, so Voldemort's death is triggered by Neville killing the snake, making him ...

Who really killed Voldemort?

During his final confrontation with Voldemort, Harry knew that he (Harry) was the Elder Wand's true master. He again cast Expelliarmus, ejecting the wand from Voldemort's hand into his own as the Killing Curse rebounded off his body, fatally striking Voldemort.

Did Neville break the prophecy?

It was eventually smashed in a skirmish during the Battle of the Department of Mysteries taking place in the Death Chamber when it fell from Neville's pocket and Neville accidentally kicked and smashed it. The destruction of the prophecy infuriated Lord Voldemort, as it symbolised Harry triumphing over him once again.