is is true that obsessive compulsive disorder gives people killing thoughts?

my brother in law.has been acting a little depressed lately. crying out of the blue.. having anxiety .he has diarreah.his blood pressure has been high. he has been having eating problems and sleeping problems he says he has thoughts of something and it won’t go away. lately he’s been having killing thoughts about his family [...] http://bit.ly/mt6RCZ