Marc Dobiecki, the C.E.O. of Commander, a film-equipment-rental company, took note. “I could kind of smell it,” he said. “I knew we were on the list, even though we’re just a couple minutes from the local police department.” Security footage from some of the burglaries appeared to show the intruders carrying firearms. Dobiecki, a former Navy corpsman, decided to sleep on site, with a gun, for “a good chunk of last year,” he said. “I invested in body armor, too, and general-protection things, to be ready for a firefight.” He added, “I had all the lights rigged where they couldn’t turn them on. I was in control of the playing field if they came in. I knew the territory.” One night, in mid-August, he wasn’t there, and thieves took a client’s monitor that was worth about five thousand dollars. “I had to pay for that the next day,” he said.