and let s not forget, let s think about david right now as well. i ve already described david. a loyal friend and colleague. a man of the people. he was killed serving his own constituents and constituency members. we will carry on. reporter: meanwhile, police are developing a clearer idea about why this attack happened. they suspect that it was an act of terrorism. they believe the 25-year-old man they are holding was motivated bylamist extremism. phil black, cnn, london. here to the united states now, where a manhunt is underway in houston for a gunman who opened fire on three police officers outside a sports bar on friday. one deputy was killed in the ambush, two others were wounded. cnn s jean casarez has more. reporter: we are told that this happened about 2:12 this morning, at a houston sports boor, in the parking lot. deputies were called to that parking lot because of something