Like, the whole of Return of the Obra Dinn lol.

My most memorable experience in solving a crime was in the infiltration of the criminal organization of H.A.R.M. to find the antidote to their Bio-weapon and the list of targets. All to save a ransomed world in the game "The Operative, No One Lives Forever." Great Game! Does anyone know what H.A.R.M. stands for?

In retrospective, solving the titular case in Under a Killing Moon.

May not be the most memorable one but it was 1994, cinematic games of that stature were rare and it was, perhaps, the first FMV-game that I played end-to-end with great pleasure. Interface was clunky as hell but it had the production values and that awesome cinematic punch, unprecedented for the time.

Also, the fact that it was the first one that came to mind when writing this post!

It is not known (from https://nolf.fandom.com/wiki/H.A.R.M.):

Finding out that I was a replicant in Blade Runner

I know. The question was meant to be a joke to anyone who played the game. Thanks.

That would easily be Deja Vu. I'd picked up Shadowgate Classic on a whim for the Game Boy Color, and really enjoyed it, so I picked up the NES version not long afterwards. My sister got really into it, too, so we decided to check out the rest of the MacVenture titles. Uninvited was good, but nothing could've prepared us for Deja Vu. You had all the usual "Collect every item" and "Pay attention, because almost anything can kill you" of the Adventure games we'd both come to love over the years, but never before had the latter been an integral part of the game design, and the former been a way to completely screw you over. You couldn't just use everything on your inventory on everything in the game you could think of until it let you move on; you really had to build a case, and make sure you had all the right evidence. What really made the case memorable to solve was that just solving it wasn't enough; you also had to dispose of any incriminating evidence that could be used against you, which was something you really had to think about. To this day, we both still quote, "Ace Harding's my moniker" in an over-the-top accent, because finally solving that case was so triumphant for us both.

I have the perfect one, I'm sure I'm going to win...

Unfortunately... I can't quite remember it...

Probably one of the more tragic endings, depending on your choices of course, is helping the Bloody Baron locate his wife and daughter in Witcher 3. And then of course how the Baron handles it.... uff!!

Most memorable was probably Paradise Killer - so original setting with gods, immortals (who were murdered *snicker*) and everybody having a beef with everybody... and there you are as "The Investigator" Lady Love Dies (what a name), able to call it quits any time and let the court rule based on the evidence you found (or not...).
Of course I had to get to the bottom of it, for real. Awesome game.

Rolgan’s Trial in the Neverwinter Nights Official Campaign.

Rachel Amber disappearance (or should I say murder...) in Life Is Strange!

Kathy Rain, that game is a nice case solving game
with awesome pixels

The Dame Was Loaded. An excellent crime-solving mystery that is nonlinear and has nine possible endings.

Gemini Rue, I was so involved in finding the lost brother that I never stopped to reflect on what was really happening untill the very end. Excelent plot, excelent athmosphere.