Who do you think is at fault in this car accident?

Full story:
I was involved in a car accident during a rainy night while I was parked. I had backed up and was waiting to proceed straight onto the street when two cars, whose lights I saw in my rearview mirror, passed by. After they had cleared, I proceeded straight and was suddenly struck by another vehicle. The moment after we crashed, I noticed that his vehicle had no lights on. However, the driver claimed to have turned them off right after the collision.
I proceeded straight assuming that there were no cars behind me as I did not open the window to check behind me, I only checked through my mirror. Given these circumstances, I am unsure whose fault it is. Could you kindly provide any insights on this matter?
I would like to mention that during the collision, my car door was severely damaged and as a result, I came close to fracturing my arm. It's worth noting that the other driver was operating a much older vehicle

/r/AskAnAmerican Thread