I'm having a tough time remembering how the clue/alibi stuff worked from just reading the English translation, but it was pretty clever. I didn't figure out how to make sense of the clues until halfway through the game when it clicked (and again, I don't remember how it worked now). I ended up figuring it out too late to actually win, I think.
If only I had noticed the thread earlier; I would've known it right away.
I probably shouldn't be saying this, considering that I know the designer and everything, but the game is not really that good, at least not for gamers. One year we had that game as part of the qualification for Europe Masters, and it is fairly broken at least as a competitive game. Due to the final scoring system, a fairly good strategy is not based on figuring out all of the clues but instead getting 1-2 (out of 3) of the categories right and then making a guess. If you know two and you reveal your guesses, you are guaranteed at least the 2nd position and have fairly good chance of winning (especially if the guess is not completely random; if you have more than 50% chance of guessing the last one then someone else probably has too, and hence you must run to the finish to maximize your odds). Given that you can (at least almost) know one of the categories right from the start and can attempt to figure out a second after a few questions, there will typically be at least someone who goes for such a quick finish. And once they are gone, there are even less opportunities for the other players to ask questions. In the end, you might go though the game asking or answering only a few isolated questions -- not much of a deduction game then.
I agree that the movement mechanic is decent, but the rest of the game is not. As a family game it could work, but it might be a bit too complex for that; figuring out the clues is somewhat non-trivial, like you pointed out.