How will you deal such a situation?

If your child is having frequent violent thoughts, there is only so much that you, as a parent, can do about it. These kinds of thoughts can lead to behaviors that are not only dangerous for your child but for others. You can try speaking to your child about his thoughts, but sometimes a solution is beyond a parent's grasp, and your child may need professional help to overcome the issue for his own sake and for the safety of the public.

Well I think the very first thing a parent should do in such situation and talk to the child. Though the parent should always remember to not pressure the childs mind for it will only lead to nothing. Try to explain to the child that having bad thoughts is normal for a person but having too much of these thoughts could sometimes ruin his life.

I don't think that having the child see a professional is not the right thing to do right away for if the child is too young,he or she will only get confuse of why you are sending him or her to the professional when all she he or she needs is a little talk with the parent.

The child and the parent should create a sort of bond and understanding to overcome this kinds of obstacles in life.:)

It would depend upon what these thoughts are,how old he is,if there was a trigger that started the problem and what behaviours are occuring as a result of his thoughts.
If you could be slightly more specific it may help people respond in a more helpful manner.

If the children start being rebellious and start behaving violently. Parents should act as friends and talk to them. Young children can be advice and taught not to behave like that. But for teenagers, they'll start having conflict and won't open up easily. Parents need to be really patient and try to understand their child.