Weird, random, open door

I had some appointments this morning. When I got home I was greeted in the garage by my next door neighbor's dog, Friday. She was excited and kept running to see me and then running back to her front door. I walked over to her front door and it was open. Curios because my neighbor is a teacher and is generally not home during the day. So, Jay called inside the house and we rang the doorbell and nothing. Friday continued to run in and out of the house. At this point I became concerned because obviously no one was home (or able to come to the door) but I still wasn't comfortable walking in and checking things out for myself. So, we called the police. They came and went inside. They checked things out and didn't find anything unusual. It is still a mystery how her front door got open leaving Friday to come and go as she pleased, but I was just relieved they hadn't been robbed or that something hadn't happened to my neighbor. She was grateful when the police contacted her and told her what had happened. I was relieved because you never know how someone is going to react, I mean I was all up in her business... But, everything ended well and that is really all that matters.