Philosophy Now Forum

Michael Rockler scrutinizes the private investigator’s existentialist credentials.

https://philosophynow.org/issues/75/Sam_Spade_Existential_Hero

Yep, along with a few other fictional detectives, including Mike Hammer.

'Hero' is a bit much, though...just plain old 'existentialist' fits better.

Rule of thumb (I think): the one who who sez he's an existentialist, probably isn't; the one who just 'does', probably is.