Can Police Officers park their Police Cars in our driveway while investigating our neighbours?

I live in a duplex in a pretty good neighbourhood. Our downstairs neighbours deal with the police on a regular basis. All other neighbours on our street are completely law-abiding citizens. I am so mad bec the police are here 3 or 4 times a month and they always park in OUR driveway! The people downstairs have an empty driveway on THEIR side of the house and the police have to walk across our front yard to walk down their driveway to get to their door! I asked one officer today to move his car over to their driveway, and he said NO. Can I call and have his police car towed? Should I have called the Police Station? We live on a VERY busy street and I so am tired of friends/family/coworkers driving past my house, thinking that the police are at my door instead of the crazy neighbours'.