I hope this is the right place for this question; someone from the TCM forums recommended that I come here.

The question is simple: who sang the three Cole Porter songs in the movie “Sleuth” (1972). The answer is far from simple, sending me down a rabbit hole of false leads and red herrings. I started with a post two years ago on IMDb, after finding out that the mystery had been going around the Internet for at least ten years.

Here's a link to a video of Laurence Olivier's character dancing to them in a scene from the movie: www.youtube.com/watch?v=4_VVr8ScGOc. One would think that by this time someone would have some idea of who sang them, but the identity of the singer just seems a mystery despite some promising leads over the years, none of which have panned out. Even more curiously, there is no singer identified? in the end credits, and the three songs did not appear on the movie's soundtrack.

It’s not Al Bowlly or Frank Luther, two common candidates for the singer, and several music professors and radio stations I spoke with said that it doesn’t sound like a real ‘30s recording at all but rather a contemporaneous (‘70s) recording trying to sound like it’s from the ‘30s.

Singer/music historian Michael Feinstein posted this mystery on his Facebook page a year ago and never got a definitive answer either.

We have one promising lead—a man named David Kernan, who had sung Porter before and whose vocals are very close: https://youtu.be/HyVqj-4Z3UI. Kernan is still alive, but unfortunately I’ve been unable to find any contact information for him or anyone associated with him.

If you are able to help, it’s really greatly appreciated.