The letters, any copies of police and court records and a lawyer who has some experience with this area of law is by far his best bet.
Just any lawyer isn't going to help much. One thing I have learned from being married to an attorney is there are a zillion laws out their. If you need legal advise you best get one who focuses on your issue. If you don't do that asking your neighbor (or this forum) might be just as effective and the answers worthless.
For example, although my wife is an attorney, I will bet serious money, I know more about gun laws than she does. She probably wouldn't know you couldn't buy a gun if you had a domestic assault. Once she studies them she could probably tell me more about how they would be applied and thee various ways they could be applied or interpreted. But, if you asked he a question on one now she would be way way behind anyone who had spend much time actually dealing with them. Ask her a question dealing with child law and you will get a very valid legal opinion. Ask her who is qualified for Social security disability and she will tell you. Criminal law, if it was serious she would refer you.
It like asking a Caterpillar vs a Porsche mechanic to look at your Porsche. Both might be the very best mechanics (technicians now days) in their field. But, 99.99% of the time the guy who focuses on the Porsche is going to get you to where you wantg to be quicker.