Do confidentiality laws apply to a State Psych/Penal institution AFTER death of inmate?

I am looking into the triple murder of 3 little girls who were my neighbors in 1977. The 16-yr old boy "convicted" of the murders was remanded to Patuxent Inst., which is a state-run facility for convicted criminals in need of psychiatric treatment. He supposedly committed suicide in this facility in 1982, when he was 20 yrs old. According to the facility, he left a suicide note. There are too many questionable issues regarding this case to go into here. I want to know if the confidentiality of a psych patient continues even after their death. ***And does this change when the patient is a Ward of the State, and their crime and punishment is public record. Doesn't the public have a right to the information in the inmates record same as we do for an inmate in a state prison. Do we have the right to view his psych record? Do we have the right to view his non-therapy records, such as the suicide note? Right now, I don't even have any proof that the note ,(if it exists), wasn't actually addressed to the public at large regarding his crime. That note is critical when the entire question of his guilt is being called into question.