BOSTON (AP) – A teenager was shot in the head aboard a public transit bus on Friday, just hours after the New York-based Guardian Angels were to begin patrols in that crime-plagued Boston neighborhood.

The victim was described only as a male teenager, suffering a “very serious” gunshot wound, said Joe Pesaturo, spokesman for the Massachusetts Bay Transportation Authority.

The shooting took place at 3:50 p.m. at the corner of Washington Street and Columbia Road in the Grove Hall section of Dorchester.

There have been 14 slayings in the city this year, compared with 10 at this time last year, though police said overall shootings were down 23 percent this year as of last Sunday.