It's the police!
The murderer was holed up in his house, and the police team was trying to get him out.
A policeman got on the loud hailer and said, "Come on out, or I'm going to come in there and drag you out!"
The murderer called back, "I'm warning you.
A policeman got on the loud hailer and said, "Come on out, or I'm going to come in there and drag you out!"
The murderer called back, "I'm warning you.
Spoiler: