This is a well-wrought action-thriller with enough menacing violence to keep a shock value high, but not enough to overcome the characters or the script. Fred Morrow (Jeffrey Hunter), a real-estate agent who stops by a bar to make a phone call, is a chance witness to a knifing by an L.A. street gang. Upset and conscientious, he picks up the phone and calls the police. Once the men in blue arrive, Fred is the only one willing to testify against the gang members -- as usual, no one else has seen anything. From that moment onward, Fred and his family are harassed as the drugged-out gang turns to any means to shut him up or to permanently silence him. Dennis Hopper is a standout as the gang's ruling villain -- the type of character he would become noted for playing -- and the rest of the gang, including singer Johnny Nash as the only Afro-American (and ultimately decent) member, are convincingly portrayed.