So, this man (I believe his name was Arthur) is a lawyer who is defending his grandfather, named Sam. His grandfather has been falsely accused of planting a bomb in a shop and killing two children with it. The lawyer investigates the case and meets a woman named Lee (who is his grandfather's niece). When Lee was young, she saw her father shoot a man, one of his workers because his son thought the worker had stolen his toy. The woman has been feeling guilty her whole life because she thought she could've stopped her father. Near the end of the movie, the lawyer finds out who did commit the crime, but he couldn't prove it. This resulted in the fact that his grandfather Sam was in fact killed with gas by the people of the law.
I have searched the internet for a very long time, I can already tell that even though the plots seem similar I do NOT mean the movie "And Justice for All", because Al Pacino did NOT play in the movie I'm talking about.
I hope I've given enough information, I've told all I remember, thanks in advance.