Little Girl And Mother At Door

After school, my friend and I had arrived at her house, and were sitting  at the kitchen table, talking and drinking soda. Her little sister was sitting with us as well, who is eight. All of a sudden, she gets up, and walks to the door. We figured she just wanted to go outside, so we continued with our conversation, but then she came back with a worried expression on her face.  

She explained to us that when she was sitting at the table, she had seen a little girl, about her age, and a woman standing outside of the door. The wood door was open, so it was the screen door that they were standing in front of. But then she told us that as she was getting up to go see who they were, she looked back and they were gone. Apparently, they were also rustling with the door handle, as if they were trying to get inside. The older one was rummaging through our mail. After she told us that there were people at the door and then they disappeared, we ran outside to go see if they were walking away. But, the strange thing is, there was nobody there. Not just in front of the house, but anywhere on the street. They truly vanished.

Shaken up, her little sister then began to describe all that I wrote above and more. It was incredibly realistic, especially hearing her saying it first-hand. She described the younger girl as very pretty, wearing a pink ruffled skirt and a pink shirt, with dark hair, and Caucasian. The woman, she explained, also had dark hair, and was wearing jeans with a brown tee shirt.

I'm not entirely sure how to classify this situation... But I have an odd disposition that it was, indeed, involving the supernatural.