From the abstract I gathered that average looking people are generally considered law-abiding whereas people with outlier features are more likely to fall into the criminal category: "The variation among criminal faces is significantly greater than that of the non-criminal faces."

Likening this to the "wage gap" where the XY chromosome is responsible for more outlier behavior: both the top of society and the bottom is both heavily dominated by male participants, whereas the female population is closer to the average and has far fewer outliers. Could this be related?

There's variance in XY chromosomes that cause men to swing wildly on the scale in both positive and negative directions. There seems to be an answer to the hypothesis that asserts that individuals with wildly differing attributes seem more often than not to fall on the outside of the law.