The first thing, I thought of was a ghost!
Or someone watching over your home. Dogs are very sensitive to spirits. Not to spook you but we believe we had one watching over us a few years back. I opened my home to a troubled teen and when she began living here, odd things began to happen......radios, tvs would turn on at odd times, unexplained noises, etc. Not to get into details but when the girls left, everything stopped! She had been stealing money and items from us....I believe the "being" was trying to protect us! So what made her leave? She had a night, where while she slept, she had what felt like a weight sitting on her stomach and it was trying to choke her!