Question on Car Accident

Last week I was involved in Car Accident. While waiting at traffic light someone hit from behind and causing my car to move forward and hit the front car. I have made the report the same day the accident happen the front and behind driver also made the report. Today when I go an collect the report, found out that I was found guilty as well. So I cannot collect the report until I pay the saman.

So want to check why I was found guilty? Because I hear from some people because my car was hit from behind then should be the last car fault. So wondering it is normal or true that middle car was found guilty as well other than the behind car?