The Lone Wolf Strikes (1940)

Starring Warren William, Joan Perry, Eric Blore, Alan Baxter, Astrid Allwyn
Directed by Sidney Salkow
(actor & director credits courtesy IMDB.com)

The Lone Wolf is hired to recover a valuable pearl necklace after it's secretly replaced with a cheap imitation, but his client is too eager to help him in his investigation every step of the way. 

Warren William lays on the charm and smooth deception as he outwits both the jewel thieves and the police in another installment in the long-running Lone Wolf series for Columbia Pictures.  It's an amusing and entertaining picture, with Blore and his comic timing and droll delivery an equal to William's talents.  The film lacks the polish and sheen of higher-budgeted productions or even the B-product of larger studios, but it's easy to see why this was such a successful series.

The Lone Wolf In London (1947)

Starring Gerald Mohr, Nancy Saunders, Eric Blore, Evelyn Ankers, Richard Fraser
Directed by Leslie Goodwins
(actor & director credits courtesy IMDB.com)

The Lone Wolf travels to London to view an exclusive pair of gems he plans to include in a book he's writing, but their disappearance after his arrival prompts Scotland Yard to follow him closely.

Another fun Lone Wolf adventure well constructed around Gerald Mohr's talented voice and Eric Blore's comic timing, the film's a very enjoyable lark, but there's not much thought expended in the screenplay towards using the British flavor of the setting to add color to the film.  I still enjoyed the production, and after seeing two of his Lone Wolf outings now, it's a shame that Mohr's run on the series didn't last longer.

The Notorious Lone Wolf (1946)

Starring Gerald Mohr, Janis Carter, Eric Blore, John Abbott, William Davidson
Directed by D. Ross Lederman
(actor & director credits courtesy IMDB.com)

Former jewel thief Michael Lanyard, aka The Lone Wolf, falls under suspicion again when a valuable jewel is stolen from Indian royalty, but has a scheme to find the real culprit.

Per Wikipedia, this was the first Lone Wolf film from Columbia Pictures after a three year absence, and the first to star Mohr, replacing Warren William after a long run on the series, although Blore returns as Lanyard's faithful butler.  Although the setup for the mystery is fairly clever, its execution relies on several coincidences and and not all the plot ends are convincingly wrapped up, but it still makes for an amusing romp.  Blore, a cinema treasure in his own right, plays very well off of Mohr, and Mohr's smooth delivery makes him a nice fit in William's former shoes.