UPDATE, Monday: Dorchester teen charged with shooting her in the head.
Dawnn Jaffier, 26, a 2010 graduate of UMass Amherst, died today when she was shot in the head during the J'Ouvert parade on Blue Hill Avenue.
Keith Williams, 18, was one of three people detained by police not long after she was shot around 8:15 a.m. He was charged with illegal possession of a firearm and illegal possession of ammunition, police say. Police did not say whether the other two men would be charged.
Jaffier was a coach at the Boys & Girls Club's Hennigan Club in Jamaica Plain, whose members and parents took to social media to mourn her loss as word spread. During the school year, she was a youth interventionist at the Hennigan School.
She was also a program assistant at the West End House in Brighton - where she was a member as a girl and teen.
She also spent a year as a City Year volunteer.
Anyone with information can contact homicide detectives at 617-343-4470. or the anonymous tip line by calling 800-494-TIPS or by texting TIP to CRIME (27463).