The other thing about the movie The Strangers, is it a true story?

Alot of those movies do that. But they use the very loose "based on true" events or "inspired by true events" but it usually is only used as a way to build interest or some kind of embracement of the movie. It usually has no relation, the remake of the texas chainsaw massacre had "inspired by true events" on it but in truth it is based on ed gein who was indeed a serial killer but did not use chainsaws or was as extreame as that movie. The truth is always usually by theme or small relations

Supposedly its based on the keddie cabin murders, but I think its mostly just made up.