6. In Chicago "Smiling Gus" Winkler met up with some of Chicago's most famous gangsters. They included:

Al Capone, Fred "Killer" Burke, and Bugsy Moran.

Explanation:

Augustus "Smiling Gus" Winkler was a big-time gangster who had his fingerprints surgically altered so as not to be identifiable through fingerprint technology. He was part of Eagan's Rats gang and would participate in some of the most notorious crimes such as the St. Valentines Massacre in 1929.

When he moved up north, he met up with some of the world's famous gangsters like Al Capone, Roger Touhy, Fred Burke, and Bugsy Moran. But in 1933, to secure himself, he turned evidence against his friends and accomplices. But he was not to be safe for long, for he was gunned down by unknown assailants rumored to be ordered by Frank Nitti on October 9, 1933.