– A BuzzFeed investigation this year found at least 29 US police dogs had died of heatstroke in their handlers' cars over the past seven years. But a new analysis of 619 deaths since 2011 by the Green Bay Press-Gazette raises that number to at least 46 dogs, with 18 others succumbing to heatstroke during other activities (e.g., training exercises, being tethered outside in the sun), putting heatstroke as the No. 1 cause of police dog deaths for non-medical reasons. Failures in the cars' AC or other equipment were factors in 19 of the 46 cases, while officer negligence was blamed in 26. One especially egregious case in 2013 involved 10 US Customs and Border Protection dogs who died after the AC failed. "Those dogs were essentially in an oven," a rep said at the time. "You don't have to be an animal lover to be sick about this." It's unclear exactly how many police dogs die this way, since agencies don't have to report it, the Press-Gazette notes; instead, stats are typically culled from memorial websites and other sources. "It is a painful, horrible death," a veterinary specialist told BuzzFeed. Departments are taking measures including replacing faulty heat-alarm units, mounting fans in car windows, and inspecting AC units more regularly. But advocates say it comes down to human diligence. "It's not a matter of changing policy," the director of a Wisconsin canine handler group tells the Press-Gazette. "Check on your dog." An Animal Legal Defense Fund director puts it in harsher terms: "An officer who allows a dog to die of heat exhaustion on duty is as neglectful as leaving a service revolver on a school playground." (A Florida officer was "distraught" after two police dogs died in his car.)