The link that Aleron posted earlier tells of several serious bite incidents involving western Washington police dogs:
http://seattletimes.com/html/localnews/2020474412_k9dogbitesxml.html
Obviously, the media is going to make as big a story of it as they can, so highlight the worst of the worst, but it still shows several incidents of serious bites involving police K-9s. And of interest is the fact that the dogs that are involved in these incidents seem to frequently to have it happen more than once.
http://seattletimes.com/html/localnews/2020474412_k9dogbitesxml.html
Obviously, the media is going to make as big a story of it as they can, so highlight the worst of the worst, but it still shows several incidents of serious bites involving police K-9s. And of interest is the fact that the dogs that are involved in these incidents seem to frequently to have it happen more than once.