Was This a Demon?

I'm very close friends with two very "sensitive" girls. Sensitive in the paranormal sense. They both told me this story and it really creeped me out. They are pretty sure they saw a demon. The two of them were walking downtown here in the wine country. It was still light out, and they were heading for the brewery. All of a sudden they see this young man, Sam, being harassed by the police. Sam is homeless, talks to himself, has stalked people, and writes about the devil. He is pretty scary to be around.

My friends keep walking after seeing him. Slowly, a car pulls up beside them. In the back seat with the window down is a teenage girl. She is leering at them. She is wearing all black, and is almost green in skin color, much like a dead person. The look on her face was so scary that my friends took off running. One of them started to cry. As they run down the street they see the same girl standing ahead of them. It would not have been humanly possible for her to have gotten out of the car, and run down the street before them. She just appeared. They hurriedly ran into the brewery, and prayed that she wouldn't come in after them. They told me they would never wish the experience on anyone. They both have seen a lot of ghosts, but never a "demon..."

They are wondering if the demon was connected to Sam. He seems to be interested in witchcraft, and has a very negative energy to him. He actually stalked one of the girls that saw the demon. This was previous to the encounter.

What do you think this was?

Thanks.