Ricochet angle/distance

I need help tracking down bullets. I have an alcoholic neighbor who fired a lot of shots at our house and struck our house about a dozen times. He was firing about 100 yards away through a row of pine trees and we belive most of the bullets ricochet off the house as there are just holes about halfway in the roof and siding with no signs of a bullet in them. The cops said we need to find a bullet for them to do the ballistics testing on before they will formally charge him.

There are a few shots that hit some soft wood trim on the house at about a 60 degree angle with about a 1/2 inch deep hole. The gun used was a 9mm and belive he was using solid lead with a brass jacket ammunition. What would you expect the ricochet distance and angle be in this case? I know there is a lot of variables that come into play, but i have been all over the yard with a metal detector with no luck.