It was about 10:30 in the morning on a cold Chicago day, Valentine’s Day to be exact, when seven men were gunned down gangster style in the Clark Street garage at 2122 N. Clark St. All of the victims, but one, (an unlucky optician who enjoyed the company of criminals) were gangsters marked for killing by Al Capone.Though Capone was the one behind ordering the killings, he wasn’t present that day. Instead he was at his vacation place in Palm Island, Fla. He had a solid alibi. No one was ever jailed for the shootings; not even the henchmen who did Capone’s bidding. The heinous slaughter accomplished Capone’s desired result, which was to permanently…