Little known tidbit -- there was a Dragnet movie released in 1954, which was the first movie based on a TV series.

The plot is a bit corny, and civil rights be damned (this is a good decade before Miranda v. Arizona), but it's worth a look just to see a pre-Paladin Richard Boone and very young, very clean-cut Dennis Weaver.

Of course, the film has a lot of the regular cast from the later Dragnet/Adam-12/Emergency! universe -- Stacy Harris, William Boyett, Art Gilmore, Virginia Gregg, Vic Perrin, just to name a few.