Let's take a look at The Unsuspected.
Shortly after, at a party thrown by Victor's other niece, Althea, a man calling himself Steve Howard shows up claiming to be the missing/presumed dead Mathilda's husband - the first anyone had heard of her having one. Victor, rightly suspicious, asks a detective he's acquainted with to look into this newcomer. In the process Mathilda is found, and claims to have never met her "husband."
Several heads are put together and eventually, almost everyone confides in each other that they believe Grandison killed his secretary, to whom Steve Howard was actually married. He concocted his ruse to attempt to lure Grandison into a confession, believing he killed both Steve's wife and his own niece.
After that, it's mostly a matter of running down the clock. Police are involved, some action scenes occur and Grandison, knowing he's trapped, goes on air and confesses his crimes to his listeners. The film ends, after a little time has passed via movie magic, with a walk through the prison yard.
The thing about the movie is that it's not really a mystery because we're shown all along the way what both Grandison and his pursuers (even before they really know it's him they're pursuing) are doing, so it's more of a mid-energy thriller than a mystery. And the more I think about it, it only looks like noir, without the sweaty, desperation that characterizes the genre. This is all very classy, very high society stuff we've got going on here.
But it's a fine film. It's not as well-known as some of Curtiz's other works, and it doesn't really deserve to be, but it also doesn't deserve to be forgotten.