A ".45 Automatic for investigation and an interesting way to "nerf" the strongest in the game.
For 4 resources and 4 actions you pick up 6 clues with a +1 bonus. Use it alongside Magnifying glass or instead of it, the compressed number of tests lends extra usefulness to Perception and Unexpected Courage and other cards with intellect icons, also large bonuses like from Fieldwork become that much more impressive. An Ursula Downs with Fieldwork and Fingerprint Kit can blast locations at 7 for double clues, 8 with Milan in play, high difficulty investigate locations aren't too common so a Eureka! would stop the gap just as well as the good doctor would.
Rex Murphy has been the strongest for a while, but giving accessible multi-clue to everyone in the class all of a sudden frees up a lot of space for fresh blood in the spotlight. Ursula Downs can trigger it on her ability, Daisy's long setups are mitigated by the added clue speed. Finn Edwards and Carolyn Fern can also make use of it. Resupply with Venturer or Emergency Cache, yeah, there's a lot of options there.
To say the least, this card is going to shift the way characters are built. Or not. Less investigations means less money from Dr. Milan Christopher. There's an anti-synergy here. I figure there will be new and divergent build paths.
Edit: A little more experience playing with it.
Fingerprint Kit is not a catch-all good clue-getter card. it is very expensive for what it does. The specific deck-tech this thing is for is to speed up a character who is doing little else, and has cash to spare. Ursula Downs or Daisy Walker, Norman Withers, characters whose actions are predominantly used to beat the clue part of a scenario. If you've ever seen these types of characters at work you've probably seen them sporting piles of 10+ resources doing nothing at the end of a scenario, this card is for them.
For a character whose role is multifaceted, such as Roland Banks or Joe Diamond, fingerprint kit falls off the radar, it's just too expensive a card for characters who need to be paying for weapons and Physical Training usage as well. For these guys there's cards like Pathfinder or Magnifying Glass, cards that are cheap enough to play in between guns or will be generating action value whether you're killing enemies or getting clues.