Before attempting to donate your dog to a police force, be aware that not all dogs will be suitable for K9 work. Many trainers work only with certain breeds (such as German shepherds) and will not take on a dog that seems less than ideal.
Most police forces do not train their own K9 dogs. Private, DEA-licensed companies purchase and train dogs to be sold to K9 units at various precincts. These same companies are also employed by police stations and individual officers to train K9 unit officers to work with the dogs.
Find a K9 training centre in your area. Contact them with questions and offer your dog as a potential K9. The representative will probably be able to tell you over the phone whether your dog is a likely candidate.
Offer to bring your puppy in for an evaluation. If the training organisation is interested and accepting puppy donations, they will tell you how to proceed.
Bring your dog in for an evaluation. If the results are promising, the training company will provide you with the necessary paperwork to donate your dog.
Though K9 training companies often offer training for dogs of all ages, most will not accept an older dog intended for lifelong K9 preparation. Puppies and very young, only moderately trained dogs are most desirable.
Know that you will likely have little to no contact with the dog after your donation. Being accepted for training is no guarantee of successful completion. Dogs which do not meet the rigorous requirements or cannot complete the training of a K9 dog are usually sold. If they cannot be sold and there is no possibility of finding a home, there is some risk that the animal may be euthanized.