Yeah, it is possible. But why would he then put LaGuarta on Dexters trail?
Unless he did it in order to create a situation where Dexter had to kill LaGuarta to be free.
And who knows, if Dexter doesn't feel bound up by his code any longer, then I suppose it is possible.
But the code has helped him from being caught before. If he turns his back on it, he will get caught.
Maybe the last episode of this show will be Dexter strapped up on a table, then given a lethal injection by the State?