My experience with suspicious black male wearing hoodie

I was at the public library in a fairly well-off part of town one rainy summer afternoon doing some writing on my computer when I noticed a tall black male with wearing jeans, a hoodie, and dark sunglasses wandering conspicuously around the library.  He would peruse aimlessly through the stacks and it seemed to me that he wasn't really looking for a book.  He then sat down at a computer where instead of logging in he just clicked around the screen for a few minutes.  His choice of garb was not fitting to the weather either, way too hot for a hoodie and why would you ever wear sunglasses indoors on a rainy day?   It struck me as odd, and given the fact that he was a HOODIED BLACK MALE, I racially profiled him and concluded that he might be snooping around waiting for an opportunity to steal a laptop or something sinister like that.  Just kidding, well, not really.

I left the library and called 911 to report him a suspicious person, then hopped in my car, and watched the police arrive from my car.  They strode into the library and a few minutes later the guy came trudging out by himself looking disgruntled.

I always wondered what had happened inside library while I was observing from my car.  I don't think it would have been appropriate police action to confront him as he was not doing anything illegal per say.  My guess is that the police walked in casually pretending it was all routine at which point the guy got scared and walked out.

I think I might have stopped crime.  I do fantasize about a scenario where I leave my laptop as bait, hide, and then violently assault the guy when he tries to steal it.  It never happened though.