It seems to reinforce the notion that defense lawyers need to do their best to work with what nature gave, or didn't give, their clients. Often, they keep a closet of clothes available, in case someone doesn't have a nice shirt and tie for court. They typically tell clients to cut their hair, shave and cover tattoos.

"I think it's a huge concern," said defense attorney Jolene Taaffe, who is based in St. Louis. "You want your client to put their best foot forward. You don't want them to look like they just came in off the street."

Lucco recalled wondering how jurors might react to defendants who looked naturally mean. "It's not good if your client looks menacing," he said.

He said that because trials are superficial by nature, it's no wonder that first impressions are so important. "You have just an hour or two to tell a person's story," Lucco explained. "Jurors don't really get to know the true character of a defendant or witnesses."

Taaffe described a recent case when a prospective juror admitted that looks mattered.

The lawyer asked a woman charged with a methamphetamine-related crime to wash her hair and change her dirty clothes before a recent trial in Jefferson County. The client didn't listen.