In 1927, at the age of 25, House underwent a change of musical perspective as rapid and dramatic as a religious conversion. In a hamlet south of Clarksdale, he heard one of his drinking companions, either James McCoy or Willie Wilson (his recollections differed), playing bottleneck guitar, a style he had never heard before. He immediately changed his attitude about the blues, bought a guitar from a musician called Frank Hoskins, and within weeks was playing with Hoskins, McCoy and Wilson. Two songs he learned from McCoy would later be among his best known: "My Black Mama" and "Preachin' the Blues". Another source of inspiration was Rube Lacey, a much better known performer who had recorded for Columbia Records in 1927 (no titles were released) and for Paramount Records in 1928 (two titles were released). In an astonishingly short time, with only these four musicians as models, House developed to a professional standard a blues style based on his religious singing and simple bottleneck guitar style.  Around 1927 or 1928, he had been playing in a juke joint when a man went on a shooting spree, wounding House in the leg, and he allegedly shot the man dead. House received a 15-year sentence at the Mississippi State Penitentiary (Parchman Farm), of which he served two years between 1928 and 1929. He credited his re-examination and release to an appeal by his family, but also spoke of the intervention by the influential white planter for whom they worked. The date of the killing and the duration of his sentence are unclear; House gave different accounts to different interviewers, and searches by his biographer Daniel Beaumont found no details in the court records of Coahoma County or in the archive of the Mississippi Department of Corrections.  Upon his release in 1929 or early 1930, House was strongly advised to leave Clarksdale and stay away. He walked to Jonestown and caught a train to the small town of Lula, Mississippi, sixteen miles north of Clarksdale and eight miles from the blues hub of Helena, Arkansas. Coincidentally, the great star of Delta blues, Charley Patton, was also in virtual exile in Lula, having been expelled from his base on the Dockery Plantation. With his partner Willie Brown, Patton dominated the local market for professional blues performance. Patton watched House busking when he arrived penniless at Lula station, but did not approach him. He observed House's showmanship attracting a crowd to the cafe and bootleg whiskey business of a woman called Sara Knight. Patton invited House to be a regular musical partner with him and Brown. House formed a liaison with Knight, and both musicians profited from association with her bootlegging activities. The musical partnership is disputed by Patton's biographers Stephen Calt and Gayle Dean Wardlow. They consider that House's musicianship was too limited to play with Patton and Brown, who were also rumoured to be estranged at the time. They also cite one statement by House that he did not play for dances in Lula. Beaumont concluded that House became a friend of Patton's, traveling with him to gigs but playing separately.

Answer this question "Why did he shoot him?" by extracting the answer from the text above.
he had been playing in a juke joint when a man went on a shooting spree, wounding House in the leg,