William OBrien , better known as Billy Porter but also known by the alias William or Billy Morton, was an American burglar and underworld figure in New York City during the midto late 19th century. He and partner Johnny Irving were longtime members of the Dutch Mob along with Little Freddie and Michael Sheeny Mike Kurtz. He was present during the 1883 gunfight at Shang Drapers saloon in which Irving was shot and killed by rival John Johnny the Mick Walsh. OBrien then killed Walsh and was himself gunned down by Shang Draper. Although surviving his wounds, he was tried for, and acquitted of, Walshs death.
William OBrien was born in Boston, Massachusetts in 1850. He was a printer by trade but began his criminal activities at a young age. By early adulthood, OBrien had been arrested in almost every major city in the United States and was considered second to no one in his business. According to former NYPD police detective Thomas F. Byrnes in Professional Criminals of America , he was described as
Source: Wikipedia