The following link relates to a forensic hospital in Australia but it will give you some idea about the function of a forensic hospital. For instance in relation to the type of patients admitted, this particular forensic hospital includes:
Formal forensic patients (people found not guilty of their crime by reason of mental illness or are unfit to plead because of mental illness).
Transferees (sentenced inmates who become mentally ill whilst in correctional custody, thereby requiring inpatient treatment).
civilian patients whose challenging behaviour can not be managed in the acute mental health system.
