Last night Dani and I went out for dinner, as we always do after Shabbat, and chose a restaurant in Monroeville (part of the mall complex but not in the main building). We had a nice dinner and, upon leaving, found the front door locked and other people standing around. The employee at the door told us that we were on lockdown because there was a shooter in the mall. Somebody asked if we were permitted to leave and she said "I can't stop you". After conferring briefly we decided to leave, as did some of the others there. (Our car was nearby and not in the direction of the mall.) By the time I went to sleep last night they hadn't yet found the guy, so I'd say that was a reasonable call.

But that's not the main point of this post. Several news articles (here's one) report that they identified the suspect by matching store surveillance video with pictures on social media. This future contender for the Darwin award had actually posted a picture of himself on Instagram four hours earlier, wearing the same distinctive clothing he wore in the mall later, but most such searches would presumably be harder.

Image search (by keyword) is not new, of course, and more recently Google offers reverse image search (upload an image and find ones like it). I don't know how well the latter works (haven't tested it). Searching "social media" for pictures matching surveillance footage is a large task unless Google has already indexed it for you. Either way, I wonder if they are also using geo-coding information when that's embedded in photos or posts to narrow the search. (Or law-enforcement organizations might have a big, private database that includes web scrapes and lots more; they wouldn't be the first government agency to do that.)

So this all got me wondering: are local police using Google to find suspects? What kind of success rate do they get doing that?