csheenwifeknife.jpg We already knew that some sort of a weapon was involved in the blowup between Charlie Sheen and his wife Brooke Mueller on Christmas day, but now it's being reported that it was a knife!

A source tells E! News Charlie allegedly threatened Brooke with the knife in the living room of her Aspen rental home, and while DA Arnold Mordkin couldn't confirm or deny the report, you can bet the truth will come out eventually!

Seriously, what's next for these two?