Certain government authorities know you're acquainted with someone who's previously been fingered for murder-for-hire but never convicted.

The "authorities" call you and threaten to murder your family; you naturally seek back-up from your erstwhile acquaintance. The police ensure they give you just enough information to track their threat back to a "person" of their construction.

Boom. You're up on a rap of "conspiracy to commit first degree murder" (or whatever it's actually called in your jurisdiction).

Doesn't seem so impossibly far-fetched does it?