called in another exterminator. turns out we didn t have bedbugs at all. reporter: the dog smelled something else entirely. rodent mites. a false positive. something the new york times is reporting an increase in. this exterminator is noticing it too. 95% of the time i go behind the canine, there s no bedbugs. reporter: in the pandemonium over parasites some wonder if dog owners are cashing in on our fear, without properly training themselves or the animal. these dogs can be between 98% to 100% accurate in finding bedbugs. but maintaining the training is very important. otherwise, the dogs will start making mistakes. they are really the most accurate tool that the industry has for detecting low-level infestations. reporter: owners are quick to defend their dogs. in fact, bell environmental allowed us to give one of theirs a quiz. this has bedbugs but the others are? they re control insects.