Hmm. After ten years, I got a simple idea that might sound as plausible for the triplicate symbol. (And no, I have no idea how I ended up with that name.
)
The names of the achievements are describing different police "ranks", or at least distinctions between experience. In a way, the symbols of the achievements remind me of insignias - Junior Detective is a simple with little flair, Gumshoe has a bit of complexity to it, and Super Sleuth is straight up golden. Maybe they are meant as rank insignias of sorts - seeing something like that on a drone view wouldn't, maybe, be too much of a stretch.
