just had this exact same problem with the neighbor's beagle across the street. i confronted her about it first and at first they said they were adjusting to a new schedule and he was dealing with seperation anxiety. she basically tied him to a tree each morning in the front yard and left to walk the kids to school and then came back to walk him later.
after a week and a half of being woken up every morning by him i finally just fb her again and said i'm sorry to be this way but i'm pregnant, exhausted, and your pup is waking me up at 8am every day and howling for an hour. it's not getting better so if you could please find another way to do your routine that would really help me out...and it stopped
so if neighbors are nice i'd go to them, if not defin go to police, but never talk to neighbors first and then police because they will know who was complaining to them and turned them into the cops and that's never good. i think you prob did the right thing by just making a report and follow up report if it continues. that way it's always anonymous