Trying to find a book

[Newt]

This may turn into a dead end, but there's a book I read a very long time ago that I can't find for the life of me. I'm sure I read it late 90's, early 2000's, but my memory is fuzzy, and it was a book I checked out from my local library, so I have no idea if it was actually published then. I don't have the author or title.

All I can remember from the story at this point was it took place in relatively modern times in cities, and involved dragons who were essentially anthropomorphic and were leading crime in their respective areas. I say anthropomorphic because I remember the main character (who I believe was human) being able to see their dragon heads and scales, but I don't remember if they could fully disguise themselves as human. The main character had to hunt them down, or something of the sort. One dragon was definitely white and one was red. There may have been a black and green one too.

Honestly I don't even remember anymore if they were the entirety of the story, but I expect they were since they stayed in my mind all these years. I don't even know if it would be on this website because I recall it being sort of obscure. Any help is appreciated.