4 year old talking about killing

[cbod]

My sister's 4 year old told his teacher today "I'll tell my daddy to kill you." My sister is divorced and my nephew sees his father every other weekend. This was the weekend he was at his dad's house and he usually takes him to school on Monday. When he's at home with my sister he plays nintendo DS games and Playstation but nothing violent. He watches regular kids shows like spongebob and backyardigans and crashbox on HBO but nothing grown up or violent. Understandably my sister is quite concerned about this comment, though this is the first time he's said anything like this. Is this cause for concern and if so what can be done about it? I suggested she talk to his father to make sure he's not watching violent or grown up shows at his dad's house over the weekends he's gone. Any suggestions would be greatly appreciated. Thank you very much.

[margypops]

You have got it as it does seem as if this child is witnessing on Games or TV something that is making him react, so we know thats not a good thing, your sister needs to be firm about it to her EX