If you are happy with the performance of your current Lothar Walther then that would be a good choice.
Since it sounds like you don’t have NFA concerns I would go for the 14.5” and add a suppressor.
I have no experience with gunshot humans. Sketch out the geometry involved between a prone crooks, the cs teams, elevations, and flight path. Is it possible the bullet continued on in the torso?
All I can recall of High Street is Surf City for a little Hang On Sloopy, Apollo’s for some fine gyros, and Buckeye Donuts. Also a slice from Sal’s Pizza.
I’ve been thinking about a 16” 22ARC or maybe even a 14.5” pw suppressed for a thermal setup. Seems like it would be pretty flat shooting out to 300 yards with the appropriate bullet.