Responding to rumors that the cops opened fire on Dzhokhar Tsarnaev without ballistic provocation, Watertown Police Chief Edward Deveau told CNN’s Wolf Blitzer that the Boston bomber was shooting at his troops when they shot him. Who shot first? Who knows? But still . . . why didn’t they withdraw? It’s not as if Tsarnaev was going anywhere, was it? Not for the first time, the Bay State’s bomber-seeking po-po launched a whole bunch o’ lead in a densely populated neighborhood.