Secondhand smoke is a proven killer.

Imagine that you are a government official charged with procuring the funds to fight one of two proven killers: terrorist attacks and heart disease.

No civilian interloper would question the word of a man who looked so much like what he was: a proven killer.

I was all alone in the middle of nowhere with a proven killer.

Meat is a proven killer linked to heart disease, cancer and other debilitating illnesses.

This one was now a proven killer; they certainly didn't need to awaken a second!

Sifting through my fly box, I fished out a proven killer.

He warned that Dallas would probably come out shooting "He's got nothing to lose and he's a proven killer."

I remind you that it is a proven killer.

Because serving up a proven serial killer as Kelly's murderer would be a lot more convincing than leaving people shocked and incredulous that I'd done it.