Re: Training data?
Yes, probably their shell suit collars were visible in the pics.
Reminds me of when I was a student. One day the cops came in to our mess hall and were going round apparently randomly talking to people, then they came over to me. Turns out they were doing an ID parade that evening, and wanted people who were roughly a certain age, height and colouring to take part alongside the suspect.
When we turned up, the guy's solicitor, with the suspect were allowed to pick which of us they wanted in the parade. The suspect had turned up in a nice suit, obviously trying to look as uncriminal as possible, then gets put in a parade against a bunch of scruffy students. When asked if he had any objections, he did say that he stood out because we all "look like a bunch of fucking students".
I remember getting 20 quid for couple of hours doing nothing except sitting round and standing in a line briefly, and the police station had a bar so we got a couple of rounds in between performances and had a great time.
The three different witnesses all picked the suspect out. He was definitely guilty, because when he was standing next to me and they were about to bring in the last one he whispered "this fucker will get me for sure because he's an ex-cop".