Bang! - Eliminating an outlaw with backfire
It seems that the Backfire card is part of the Valley of Shadows expansion...? 

If that is correct, then this product description geeklist from boardgamegeek, states that the outlaw is now the target of a Bang! and thus eliminated by a Bang!

https://boardgamegeek.com/geeklist/205880/item/4492671#item4492671

(And this question seems to have a duplicate : Bang! Elimination Award For Henry Block and Backfire
They seems to have been created almost simultaneously )