The Rambam, and many other Rishonim believed that divine providence extends to people in accordance with their righteousness. It follows that they believed that many times, G-d lets things happen according to nature or coincidence.
However, this seems to fly in the face of Mishpatim (21:13):
One who strikes a man so that he dies shall surely be put to death.
But one who did not stalk [him], but God brought [it] about into his hand, I will make a place for you to which he shall flee.
In this Pasuk, the only stated alternative to someone acting on his free will, is that G-d caused it to happen. According to these Rishonim, there should also exist the alternative that it happened by coincidence. How would these Rishonim explain this Pasuk?