New York: When the New York Police Department acquired a robotic dog last year, officials heralded the four-legged device as a futuristic tool that could go places that were too dangerous to send officers. “This dog is going to save lives,” Inspector Frank Digiacomo of the department’s Technical Assistance Response Unit said in a television interview in December. “It’s going to protect people. It’s going to protect officers.” Instead, the machine, which the police named Digidog, became a source of heated debate. After it was seen being deployed as part of the response to a home invasion in the Bronx in February, critics likened it to a dystopian surveillance drone. And when officers used it at a public-housing building in Manhattan this month, a backlash erupted again, with some people describing the device as emblematic of how overly aggressive the police can be when dealing with poor communities.