Private Gentiles was probably born in Ireland September 28, 1828, and entered the U.S. in 1856, perhaps illegally. He served in Co. K, 10th Infantry from 1856-61, entering Utah as part of Johnston's Army. During the Civil War he served in various Missouri units, from early 1862 to July 1865. In June 1867 he enlisted in Co. F, 14th Infantry which eventually brought him to Fort Douglas. His unit was ordered to Fort Robinson, Nebraska in 1877, where Pvt. Gentiles was absent from his appointed place of duty and subsequently punished by a Court Martial. Forfeiting $12.00 pay (nearly a full month's pay for a private) he was also sentenced to twenty days hard labor on August 13, 1877.
Following completion of his sentence, he found himself assigned to guard duty at Fort Robinson on September 5, 1877. . Although not technically a prisoner, Chief Crazy horse, implicated in the Custer Massacre of June 25, 1876, was being held at the guard house. Some sort of disturbance broke out.
Records describe the incident as one in which Crazy horse ran from the guard house "impinging upon the bayonet of No. 1 sentinel, who had instinctively lowered his piece to the charge on hearing disturbance. I am satisfied that the wound received by the latter was occasioned by the blind recklessness of his wild rush."
Chief Little Big Man is reported to have pinned Crazy horse's arms behind him, thereby facilitating the fatal bayonet thrust.
Fearing retribution from Indians, Pvt. Gentiles was quietly shipped back to Fort Douglas on the Union Pacific Railroad the following day. Less than a year later, on May 20, 1878 Private Gentiles died from an asthma attack, and was buried in the Fort Douglas Cemetery. Another nearly anonymous solider, remembered for killing a famous Indian chief under somewhat murky circumstances.