Boston Police, in particular the department’s BPD Youth Violence Strike Force, were kept very busy over a 90-minute stretch on the Monday holiday dealing with two instances of firearms-related activity, one of which involved unruly crowd behavior At about 4:30 p.m., members of the Strike Force arrested Donta Lewis, 28, of Boston, and Lamont Jacobs-Barrows, 21, of Walpole, on