i have a childhood friend who's dad is a big k-9 buff.
they own 4 of them. trained right here in the US.
there's two different types of police dogs. there's detection dogs, and then there's attack dogs.
the ocd ones are the detection ones, there's a lot of bloodlines that provide suitable attack dogs. some of these can provide both detection, and attack dogs, these are the crem of the crem, and usually go towards private security firms protecting high-profile people.
a good detection dog costs about 8,000 USD.
attack dogs run about 5,000, for a 6 month old, semi trained and ~6200 for a 1 year old fully trained.
those dogs are super trained to ignore other animals. a cat will distract a dog searching your car, but not for too long. the dog will ignore the distraction with good training. detection dogs that repeatedly fail distraction situations are retired (not euthenized, most of the time some cop keeps the dog).
look for k-9 distraction training on youtube. you'll see what I mean.