BOSTON (AP) – An investigation has began into the cause of the Boston Fire Department ladder truck crash Friday that killed one firefighter, critically injured another, and tossed glass at a half-dozen children.

Department spokesman Steve MacDonald said Saturday that the department will convene a board of inquiry to look into the cause and come up with recommendations. He declined to comment on reports that truck’s brakes may have failed in the accident.

Lt. Kevin Kelley, a 52-year-old father and a 30-year veteran, was killed when the truck crashed into the Mission Park high-rise after returning from a routine call. Another firefighter aboard had a broken leg and two others had minor injuries.

MacDonald said only one of the firefighters remained hospitalized.