This is murder. This is murder. It was ruled by the police a justifiable homicide. But "The Killing of Randy Webster," the powerful and gripping CBS movie at 9 tonight on Channel 9, reopens the case and renders a sobering verdict against gun justice in America.

The film, written by Scott Swanton from a Texas Monthly piece by journalist Tom Curtis, begins as Webster, 16, is still alive, a disaffected and confused kid living in Shreveport, la. People in his life take turns failing to understand him; he's something of a hellraiser, but a benign one.

Doubts about his life and disagreements with his parents send him, however, off on a joy ride to Houston, where he steals a van from a car dealer and proceeds to lead police on a wild chase through the city at 100 m.p.h. At this point his story goes from unfortunate to tragic; he is apprehended by the police and shot to death.

Because a gun was found near the body, the police rule the officer acted in self-defense. He tells a grand jury that the youth was brandishing a gun when he emerged from the van after the chase. But the boy's parents are not satisfied. They don't believe their son was on drugs, as is claimed, nor that he was capable of raising a gun toward anyone.

Through their own stubborn perseverance and the help of U.S. attorneys, they learn that their son died meaninglessly. While beating him to the ground, a cop accidentally shot him in the head with a drawn gun. The weapon the boy allegedly had been carrying was in fact planted by the police; in cop parlance, it was a "throwdown," planted at the scene to make it look as if the police did not shoot an unarmed victim.

Hal Holbrook, getting crustier and more credible all the time, plays the boy's father with a perfectly modulated mixture of determination and remorse; the father feels guilty, as do others in the boy's life, that they gave him grief when he needed help. Holbrook may be getting typecast as the over-anxious, culpable dad -- he played the father of a teen-age prostitute in the similarly superior "Off the Minnesota Strip" -- but he handles these roles very well.

Dixie Carter is easily as impressive as the boy's mother, and Nancy Malone is the soul of diligence as one of the U.S. attorneys. The other is Richard Beauchamp, and it's something of a relief, even within the context of this grim and depressing story, to see "the feds" portrayed as good guys and not as scapegoats. The last TV movie to risk this was "Crisis at Central High," a straightforward account of integration in Little Rock; for its trouble it was rewarded with low ratings.

The film is a model of good casting, starting with Gary McCleery as the doomed kid. The boy is stranded in the straits of indecision in which many teen-agers find themselves. Suspended from school for a third time, he attempts to join the Navy because, he tells the recruiter, "I want to be part of something bigger than myself." He is exasperating to those around him in the way that very cherished people can be.

Swanton's script gradually reveals the horrible details of the shooting in sequential flashbacks through the film. In the last, the beating of the youth is made appropriately graphic and shocking. Sam Wanamaker, probably better known as an actor, directed the film with the most functional kind of no-nonsense clarity; it's a kind of styleless style well-suited to TV movies based on real events.

How real is this event?CBS says that "while the story is true, fictitious names are used for all of the characters except the Webster family and journalist Tom Curtis." Certainly the issue of trigger-happy policemen is not something that had to be invented. "The Killing of Randy Webster" will go on the record now, and all those who were part of this film can safely say they were part of something worthwhile -- a rare claim in network television, and one to be proud of.