Rock Sponsor (Level 1)
I have an almost identical situation with the opposite outcome. Never found who hit it.Someone hit my mailbox a few years ago and knocked it off the post plus bent the post. I discovered it the next morning when I saw my box laying in the middle of my driveway. The only thing they left behind was a trim piece off the side mirror. It had a part number as well as the color of the car on it.
With the information, the police were able to find what model and year vehicle it came off of and then they did a search for a vehicle that fit that description registered to anyone in my area. They found the owner rather easily, not too far away. I agreed to not pursue any charges in exchange for them paying me for a new mailbox.
Anyway, do you know if the police did something similar with yours?