It’s in their eyes,it always is.
Oh please, spare me the asinine amateur psychology/pharmacology based on pictures.
People were making similar diagnoses OF THE WRONG PERSON when it was Ryan Lanza's picture out there.
The only reason you see anything is that YOU ALREADY KNOW THEY ARE MURDERERS.
Without that knowledge, they're just random goofballs and you wouldn't take a second glance at their pictures.
Given a random selection of 10 pictures of goofy looking white guys aged 16-25, with 5 of them just being random goofy looking white guys, and the other 5 murderers, you'd do no better than chance picking out the murderers.
I have an uncle that is a retired prison guard. I remember him telling me 25 years ago that they (guards) were always extra cautious around inmates whose eyes showed more white than color. Even the other inmates knew that white eyes were more than a little off.