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He talks directly to the murderer, who he usually suspects early on
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He lets them know a large amount of his progress (though not all), relying on them to try to further incriminate themselves by covering up sloppily
Benoit Blanc does kinda do both these things with Marta, the difference ends up being the twist that she isn't actually the murderer, she just
thinks she is an is acting accordingly. He cottons onto the blood spot on her shoe and knows she was present for the suicide, and by the end of the movie it's clearly that he definitely knew she was trying to covertly cover up her involvement, even if in the moment he didn't comment on it. That seems fitting with what you've described here.