How genuine is the detective portion of this game? Are we talking Sherlock Holmes: Crime & Punishment or something worse?
Much, much, much worse. It's not a detective game.
You go to a crime scene and you look for three "clues" that have sparkling edges, and you hit "A" on them, which causes your character to pick it up and talk about it. Every crime scene has 3 clues. If you "find" all three clues then it unlocks certain dialog choices in each mission. "Finding" clues literally comes down to walking around in a circle pressing "A" on items that are shimmering on the ground.
Here's what's makes it even worse.
There's tons of plain junk laying around on the ground in each crime scene that you can pick up, which is supposed to make you -- the player -- use your skills of detective deduction to figure out something, but it's all arbitrary. But it's all arbitrary and stupid. In an early mission (this isn't a spoiler, it's incredibly stupid and pointless), your character "finds" a match book and that leads him to go to another locale which eventually helps pinpoint the crook. This is treated as a big "Aha!" moment in the game. But... in every other mission as the game goes on, match books are just normal junk strewn around a crime scene, and the character scolds the player for 'wasting his time' or whatever on pointless non-clues for the rest of the game. So, in one mission, a matchbook is a major aha! moement in solving a caper, and yet, for the rest of the game, matchbooks are just random junk.
So, the result is, you walk around a crime scene aimlessly clicking "A" on everything. 90% of the time it's just junk and Cole, the cop, talks to himself about wasting time and not figuring out the mystery. And then 10% of the time a random piece of junk will trigger a unique dialog that's a clue to solving the mystery.
It's a shitty game. I could rant about it much longer. First 2 crimes are pretty good, then yhou realize the rest is junk. The game world is pretty, but empty, with really bad street design and nothing to do.