Which outlaw from the wild west who only turned 21 years old, is said to have shot one man for every year he lived?

Explanation

The outlaw Billy the Kid's (1859-1881) real name was Henry McCarty but he was also known under the alias' Henry Antrim and William Harrison Bonney. He participated in the Lincoln County War and it is said that he killed 21 people - one for every year he lived. There are many theories about his outlaw debut. One in which he stabs a man for molesting his mother and an other in which he steals clothes from a Chinese laundry. Billy was shot, unarmed, in the night by the Sherif Pat Garrett, who he had earlier escaped after being sentenced to death.