It's hardly a scientific study, is it? Show me some stats. Is he the 19th sniffer dog to die of the cancer this year? Is there a serious increase amongst sniffer dogs compared to any other dog? If he's the first police dog to die of nose cancer - and I'll bet there are hundreds more who've gone of various diseases and cancers in the past - then he's just following the normal trend.
Christ, if he's the first sniffer dog to die of nose cancer ever, out of hundreds or thousands, they might have inadvertently offered proof that sniffing Charlie reduces the risk.
Uneducated Plod jumping to conclusions.
Still feel sorry for the furry little bugger, though.