Does free will exist?

First of all, I need to say that, even if it is ignorant, I even do not bother to read philosophical speculations.

I am interested in empirical premises. I've heard that there is some research, where scientists, monitoring activity of a person's brain, are able to predict which switch (s)he's going to switch, before (s)he does, or maybe before (s)he's conscious about the choice. This implies that our decisions are results of some chemical processes determined aside of our "free choice" and so called free will is only an illusion, a way in which alternatives presents to us, while the choice is made already deep in our minds unconsciously and maybe even deterministically. Does anybody know this research and could cite it?

Since I am constantly busy, I really sucks in the theory, so could anybody say what's the Marxist stance on free will if any?