My six year old boy has the same problem

My six year old said: he would like kill somebody once or twice when he got angry. He felt sorry very quickly later on. But he couldn't control himself. The anger control him. I talked to him very serious several times.
I ingored him a couple days when he said bad words.
It may not work quickly, but sooner or later he will get it.

I will never contact social worker. It is hard to get rid of them, especially you spunk your son!! It is their job and they are eager to catch your mistake.