I remember seeing this in the 70s when it was airing on CBS, but I don't think I've seen it since, although I do remember seeing the pilot movie in the early 80s. I used to enjoy it, after getting interested in gangster stories. There seemed to be renewed interest in the subject in the 70s following the success of The Godfather, parts I and II, and the television premier of Bonnie and Clyde. There was at the time a slew of similar movies, mostly made-for-TV. I'm surprised this show didn't last longer. I doubt there's much demand if any for a DVD release, but it would be nice.
BTW, according to the Complete Directory For Prime Time TV Shows, the official title of the show was The Manhunter, and it also says that it was Dave Barrett's best friend's murder that motivated him to hunt criminals.