Presumably if it was easy to tell killers by their looks, they'd find it considerably harder to get away with the 'serial' part.

I got 9/10

But I think I know why... I started going partly by the style of the photograph, and partly by facial expression, but not their actual face.

[Edit] shame it's not random or a pool larger than 10, I can't do multiple trials to figure out if I just got lucky.

Even just applying filters or some more recent, casual killer photos would be helpful. For some, the "photo scanned from newspaper" look was identifiable.

Same here. It didn't help that his T-shirt was similar in colour to the stereotypical orange prison jump-suit :)

Lol