The teenager, Heath Campbell, was shot in the head, the police said. Another boy, 16, who has not been identified, was shot in the shoulder and was in stable condition.

Responding officers found the younger boy in the building’s lobby suffering from a gunshot wound to the head. The older boy was in a third-floor hallway, shot in the shoulder.

A Brooklyn community is mourning the loss of 15-year-old Heath Campbell, a high school sophomore whose life was cut short by gun violence in East Flatbush. A vigil was held as family, friends, and anti-gun violence advocates gathered to support Heath’s grieving mother,