The police officer did not drive that van at a high rate of speed through a residential neighborhood. That officer did not run off the road and hit that tree. That police officer did not prevent those four people from wearing their seat belts. That police officer made an observation that the lights were off then he turned around to observe the vehicle. As far as I know there is no law that says that the police officer must turn his lights and sirens on when he sees a suspect vehicle.

With the criminal background of the driver, if the officer had turned his lights and sirens on, the driver probably would have gone even faster than he already was. If that had happened, then the story might have ended in more tragedy had they approached other vehicles or any pedestrians. As it turns out, only the ones in the wrong were injured or lost their lives. And by not turning his lights and sirens on it is possible that that officer saved innocent lives from being lost.