An Opportune Killing

Carmen Brown begins her day the same as any other day, but on this day her life would change after seeing a stranger that seems to know her every move. After getting off of work, she noticed the stranger from earlier that day in the parking lot. He finally asked her for some spare change, but when she rejects him he disappears. she sees him a couple of times before arriving home and each time, he just disappear. now she's convinced that she's tired and is imagining these encounter so she goes to sleep. She wakes up the next morning realizing that it was just a bad dream until she talks to her friend that tells her about the events that happened last night. In carmen's dream, she kills the stranger, but there's no crime scene even though she wakes up with a knife in her hand. So what really happened that night? Did carmen kill him or was it just a dream? if it was just a dream, why does carmen's friend know the event of that night and what happened to the stranger