#1 Barking - which is bothering somebody.
#2 Protecting your Dog- even if your dog wasn't bothering anybody; it really puts your dog at risk to leave it outside when you aren't at home. Assuming nobody was agitated at you &/or your dog; a dog left in a yard is at risk from somebody opening the gate and letting the dog out whether out of malice or some delivery person thinking it is safer to put a package in your back yard - had FedEx, UPS, and USPS do this to me when I lived in Alexandria, VA -- they didn't close the gate back after delivering package, so when I let my dogs out in my back yard out the gate they went. A loose dog a huge liability as it might innocently scare an adult of child who is afraid of dogs and cause them to fall and injure themselves -- not to mention the risk for getting run over.
Dog nabbing -- either snatching the dog to try to get a reward from you or dogs snatched to be used in dog fighting for training (bait). Both of these things were MAJOR problems when I lived in the city.
Now add that the barking is irritating somebody; you have been fortunate that they called AC and didn't poison your dog; let the dog out of the yard; snatch the dog and haul it to a shelter in another town.
People are NUTS; and when you leave your dog home alone outside in your yard; that dog is at risk from any of those assorted nuts. Your dog is a lot more at risk left outside when you aren't home in a suburban / urban environment than out on a farm in the country due to the numbers of people in close proximity to your house.
The citronella & shocking bark collars may work or may not; but use those while you are at home -- while you are gone; secure the dog inside w/ windows closed and TV / Radio left on.