I think it's a shame that Charles McGraw didn't continue into the actual series - he had an amazing, rough voice that really stands apart, but so far as I know he was the never the star of a series (though he took the lead role in various episodes of Escape, for instance). I can't complain about Dan Duryea though - his voice is also quite distinct. To hear him on The Man from Homicide is to imagine the actor sneering at you; it gets to be a bit of a one-note performance, however.
The series' tagline is "I don't like killers." Duryea utters the phrase a minimum of twice per episode (always in the intro and outro; often somewhere in the drama too). He says this line with such a withering contempt that I'm not sure who he's upset with. Who is it that does like killers? Certainly old-time radio was filled with tough male leads in the crime/detective genres, but Lt. Dana's venomous disposition makes him perhaps the most hard-boiled character on radio. If the series had been made 20 years later, he would've been a Dirty Harry-type - a psychopath just barely walking the line, constantly being called out by his superiors. But although Lt. Dana has a reputation in the series (an amazing number of everyday people remark they've heard of him before when he shows up to investigate a murder), he's not really that cruel. His tough guy act is really an act.
The thing of it is, the Man from Homicide was not that hard-boiled in terms of content. There were cases involving drug abuse and one wherein the victim is said to have been shot in the face with a shotgun, but it wasn't presented with the stark realism of Dragnet that so many other shows circa 1951 were trying to emulate; the Man from Homicide's plots could've been given to a happy-go-lucky detective like Richard Diamond without too many changes.
What becomes unintentionally hilarious (aside from Duryea always being 110% angry at people) is that nearly every episode, Lt. Dana gets knocked out. That was a cliche in 1951 that other radio programs were making fun of, which makes it all the more amusing to notice how often it happened to Lt. Dana. You can just about time the moment where he gets hit from behind using a stopwatch.
There will probably be more episodes of the Man from Homicide recovered in the future, it was a reasonably late show. And it's not a bad show - I think it goes too far over the top and becomes campy, but Duryea's performance is interesting enough to keep one engaged.