sweet dreams

I've had dreams about murder the past two nights in a row. I'm not sure if that means anything.
The first dream was one I think I had before - it seemed familiar while I was dreaming it, and I'm not sure if it was really lucid dreaming (I don't think I really knew I was dreaming at the time) I nonetheless knew how everything was going to end. Is there such a thing as foreshadowing, precognition in your sleep? This dream had more of a wistful feel than a horrified one, as the people (a group of girls of which I may or may not have been a part) who were murdered were able to "come back" once or twice, in some form not quite ghostly but certainly no longer alive. The most poignant part was when one of the last girls (played by Katherine Moennig in my dream) to be killed came back, and was visiting her mother - the girl no longer lived at home, and for some reason was prone to long absences, and so her mother didn't know that she was dead. She thought her daughter was just dropping in for a visit, and at the end of their time together, the girl had to tell her mother to get someone to check her apartment - not to do it by herself.

The dream I had last night is less clear in my mind, more chaotic and confused. It was all about accidents, and mistaken identity, and good guys who have to do something bad, or think that they have to, to protect themselves. It ended with the "main character" forcing the ostensible "bad guys" into some sort of acid swamp where they would die a horrible death, leaving behind no bodies and no evidence. At the very last moment, however, something/ someone intervened, saving the good guy from becoming a murderer, but also catching him in the act of becoming a bad guy.