A man (27) is due to appear at Belfast Magistrate's Court this morning in connection with an alleged intelligence-gathering operation by dissident republicans.
He is charged with four counts of collecting information that is likely to be of use to terrorists.
Four other people arrested over the incident, in which medical records at the Royal Victoria Hospital in Belfast were being accessed to target certain figures, are still being questioned by police.
The "Real IRA" is believed to be responsible.
Details of police officers, politicians and members of the policing board and newly created district policing partnership boards were accessed, it is alleged.
One of those arrested is a member of staff at the hospital, understood to be a clerical officer with access to the password-guarded records.
The hospital, in the heart of republican west Belfast, confirmed one member of staff was among those arrested and being questioned about a "serious breach of patient confidentiality".
The hospital is the largest in Northern Ireland and treats more than 500,000 patients a year. It holds records on all of them, including home addresses.