Who can I interview and where can I find information?

If I can interview anyone I would interview people that have been in prison before. I would also interview some witnesses that have or had a family member or friend that has been or is still in jail. I want to interview these type of people because i think these people have a good understanding about how the USA has more people in jail then any other country in the world. I would also like to interview these people because they probably have a good understanding to what I'm saying,how important it is and finally how serious it is.