Than you Nir, you’re right about the reading.
Actually, this “troubled” but efficient inspector is known for being a bit?too much fascinated by sadomasochistic games, and suspected to have some practice. When he comes too close to the duo he is investigating about, they compromise him and make him suspected of being the author of the next crimes. so everything is about the A story.

Maybe the following logline would be better?
“Investigating a series of sadistic crimes, a shady Inspector must protect the only survivor and thwart the machination of a sadomasochistic duo to prove his innocence.”

It seems like “sleazy” or “shady” or “fishy” sense is too strong, unless the French translation “louche” doesn’t mean exactly the same thing: there is only a doubt about his sex morality. He frequents ?SM world and/as this is his investigating spesialism.? he is suspected to like and maybe pratice “light” SM games, but not to be violent or dangerous.