" early 20's, close cropped hair, slender...no scowl, no visible tattoos, no signs of too much red meat. Looked like he could have just stood up and walked out into the pews, sat down and blended right in. "
Remember, he was likely cleaned up for court. Think about all the out of place " dressed up " people you see on the news in court.
Behavior is a pretty good indicator. Years ago I worked at a car lot and could get a very good read of someone's demeanor just by observing the car they drove, the way they got of said car, closed the door and walked across the lot. ( No, I was not a sales person where reading people is a art. )
A sticker on their car that has Calvin peeing on something is a big red flag that they are going to be a jerk.. . .
A couple of other examples are the guy that threw a cup of liquid at a basketball game that started a riot. He didn't present himself very well on TV.
And recently, a guy that got ejected from a baseball game ( in PA? ) . While being ushered out he purposely reached around a couple of guys and pushed a stadium official. The city police interceded, guy got even more belligerent , cops hit him on the shoulders with a nightstick ( didn't even faze him ) then was taken down by force. He then claimed " police brutality ". Judging by vid of the incident and his demeanor in a TV news interview, he is a jerk in real life too.