The pair of bombs that exploded along Boyl­ston Street a month ago took not only lives and liveli­hoods, they also took with them a sense of secu­rity that many Bosto­nians once had.

And now, a month after the Marathon bomb­ings, another inci­dent has brought into ques­tion the region’s vulnerability.

Seven people were found tres­passing at the Quabbin Reser­voir at about 12:30 a.m. Tuesday. The reser­voir is the main source of water for most Boston and the city’s sur­rounding communities.