Brocius is thought to have been born in 1845 and arrived in Arizona Territory from Texas or Missouri in about 1878, bringing a herd of cattle to the San Carlos Reservation. Afterward, he went to Tombstone, Arizona, where he was a vicious, drunken gunman, cattle rustler, and murderer.
In July of 1881, Curly Bill, along with Johnny Ringo, killed William and Isaac Haslett in Hauchita, New Mexico, in revenge for the deaths of Clanton members Bill Leonard and Harry Head, who had attempted to rob the Haslett brothers’ general store some weeks earlier. A few weeks later, Brocious led an ambush attacking a group of Mexicans in the San Luis Pass, killing six and torturing the remaining eight.
After the death of “Old Man” Newton Clanton in another ambush in Guadelupe Canyon in July, Curly Bill became the leader of the Clanton Gang. After the Gunfight at the O.K. Corral in October 1881, Brocius attempted to kill Virgil Earp and assassinated Morgan Earp. In looking for revenge for Morgan’s killing, Brother Wyatt reportedly caught up with Brocius on March 24, 1882, and killed him with a double shotgun blast to the chest. This account, however, was reported by Wyatt Earp himself and many historians doubt the fact as Earp was known to have exaggerated some accounts.