A little before 11 p.m. on a hot summer night on Hanover Street, everything in the North End was business as usual. Old-school locals talked in an animated huddle on the sidewalk, pausing in unison to watch a new-school neighbor passing by wearing a Connecticut-tight ponytail and dressed in head-to-toe Lululemon. The owner of Dolce Vita Ristorante serenaded the last patrons out of his eatery. And a line of people seeking arguably the nation’s best cannoli stretched outside Modern Pastry.

This nightly ritual is part of the lifeblood that pumps through Boston’s Little Italy, as well as through the veins of Patrick “Pato” Mendoza—a wiry 54-year-old with gray braids and bad-boy good looks—who pedaled by on a bike that evening with a snub nose .38 revolver stuffed in the waistline of his pants.