That's the end of the picture. But it's not the end of the mystery!

The List of Adrian Messenger (1963)

Chosen by me as it was £3 in Fopp and sounded fun.

Unfortunately it wasn't. Though claiming to be a 'gleeful black comedy' there's no funny to be found here for the most part. It's easy to see how this seems mostly forgotten now, it's central gimmick is a dud.
The cameos from a host of Hollywood legends in make-up utterly banal.
The actual mystery (not the spot the star game, which it may cheat at anyway) is mostly compelling until it utterly deflates itself and the film spends way too much time on foxhunts (possibly at Huston's request who had the James Bond spoof Casino Royale rewritten to fit the 'sport' in).