Tex Murphy, Gabriel Knight 2, or The Black Dahlia if it really is a 90s sleuth game with FMV. There aren't many to choose from in that category ...
If it's Tex Murphy I will orgasm all day long. People will stare. I won't care.

FMV stands for Full Motion Video. It doesn't have to be shot with a camera, it can just as well be animated. Diablo II, for instance, has kickass FMV cutscenes, and those are animated.

There was also a small series of Sherlock Holmes games which seem to fit the bill.
[url=http://en.wikipedia.org/wiki/Sherlock_Holmes:_Consulting_Detective]http://en.wikipedia.org/wiki/Sherlock_Holmes:_Consulting_Detective[/url]
Not sure if they are any good though.

The ultimate sleuth game, Clue (or, for those of us outside the US, Cluedo), also had an FMV release in the mid-1990's.
The early to mid 90's was full of people jumping on the FMV bandwagon, then jumping off again when they realised what a terrible job they were doing of it. I wonder how many other FMV sleuth games people can think of before the announcement.

Black Dahlia FTW !

noooooooo i was hoping for final liberation !!!

Haha Wow, that remark takes me back. That game was fantastic!

Oooh. Tex Murphy. GOOD guess.

not just fantastic it rocks

I tweeted Myst as a guess. Its the first thing that sprung to mind. Its use of FMVs throughout the game, its THE biggest 'sleuthing' game there is, it was published in 1994 and Ubisoft is already on-board.
I agree! Though my guess is educated, I don't think its right, its just the most measured thing I could think of without yelling every PC release in the 90's.

Myst.. Urgh. Not Myst! Am I the only one that doesn't like that game?!

Yes you are !

Lets wait and see then! *Taps foot* :P

Would love it if it was Myst: Masterpiece Edition, c'mon GOG make it happen.