Don't trust ugly people

Science has proven that all ugly people are evil.

"We find that unattractive individuals commit more crime in comparison to average-looking ones, and very attractive individuals commit less crime in comparison to those who are average-looking," claim Naci Mocan of the University of Colorado and Erdal Tekin of Georgia State University.

Why would that be? I can think of some reasons:
-People tend to correlate beauty with "goodness". Whatever your expectations of someone, they tend to fulfill them. Steve from The Fat Man Walking wrote about this recently:

One of the most difficult things about being overweight is that your inner demons are obviously on display at all times. People judge you and act differently when you are around and this seems to be an attempt to keep you at arms length. As a result of this you act differently and become defensive, eventually you look for people to treat you poorly and as if on cue, they do.

-Maybe ugly genes group with other undesirable genes. Beautiful people usually have more choice in who they procreate with, so they might get all the honest, compassionate ones. Ugly people generally can't be so picky, and so all the undesirable genes get lumped together. This is just something I just thought of. I hope it's not true, because it's depressing.
-Attractiveness is probably related to self-esteem, and self-esteem is probably related to propensity to crime.
-Attractiveness probably alters your perception of the world. I remember someone once - somewhat humorously but also seriously - proposed an explanation why people at political rallies are below-average-looking: if you're unattractive, you perceive that society is not working out for you and needs changing. If you're attractive, everyone treats you well and people buy you stuff and hold open the door and fall in love at first sight. You like the status quo.