The man who fatally shot a 15-year-old boy and wounded a second teen on Memorial Day in 2011 was sentenced Friday to 67 years in prison, federal prosecutors said.

Eugene A. Kelly had expressed a desire to avenge his brother’s death, which occurred three years earlier, prosecutors said. But they said his teenage targets had nothing to do with his brother’s killing. U.S. Attorney Ronald C. Machen Jr. said the decision to shoot them was inexplicable.

Isaiah Harris and his friend were walking home in the 1400 block of New Jersey Avenue NW around 10:15 p.m. when Kelly, riding a small trick bike, opened fire. Harris was killed by a single gunshot; his friend was shot in the leg.

Kelly had believed someone from the 5th and O streets neighborhood was responsible for his brother’s death, prosecutors said, and the teenagers were walking in the area.

Kelly, 28, of Washington, was sentenced in D.C. Superior Court on first-degree murder and other charges, according to the U.S. Attorney’s Office. He was found guilty in April 2013.