I thought a couple of Steve Warner's recent Dark City shows were very interesting, although also not really in the "mystery" sphere, either.
The most recent was a show about Countess Elizabeth Bathory (15th/16th century serial killer):
https://soundcloud.com/dark-weekend/professor-kim-craft
And back in December he had a show in large part about the CIA running drugs in Florida, a bit of it about a man named Barry Seal, who concidentally Tom Cruise just
signed on to portray in a film called Mena:
https://soundcloud.com/dark-weekend/...-to-terrorland