Walter Sumter was 18 when he was shot once in the chest just after midnight on December 30, 2011, on West 154th Street in Harlem. He had been at a party attended by about 25 people and was found outside 254 W. 154th St.; he was taken to Harlem Hospital and pronounced dead. Friends and people from the Police Athletic League’s Harlem Center remembered him as well-mannered.

Investigators focused on a violent rivalry between young residents of the Grant and Manhattanville housing projects and looked into whether an altercation at the party precipitated the shooting. Early in the inquiry the brother of a local murdered basketball player, Tayshana Murphy, was questioned and released. The probe eventually led to the arrest of Taylonn Murphy Jr., and prosecutors said the killing was retaliation after Sumter allegedly mocked Murphy’s sister in an online video; prosecutors said Murphy had posted Dead on sight beef and two weeks later Sumter was killed.

Murphy was convicted of murder and conspiracy by a jury in April 2016 and sentenced in June 2016 to 50 years to life. Did anyone who knew Walter or who was at that party see anything that could add detail to what happened that night?