Alsations aren't used as drugs dogs in this country - they are used as either general purpose and body recovery dogs.
The person is probably lying in order to scare your friend off.
Even if your friend isn't lying, the dog is out of control and the police will deal with it.
Worst case... it was a drugs dog, and your friend had drugs with the,..... if the drugs aren't found, nothing will happen.
But from what you've said, they are trying to scare your friend into keeping quiet.