HARRISBURG (AP) – PA’s largest public pension system gave a little more detail about a federal probe, saying the agency received a subpoena, although it is staying silent about subpoenas said to have been received by top management officials. Officials at the Public School Employees’ Retirement System and board members have declined to answer questions publicly about what information federal investigators are seeking. In a brief statement, the $64 billion pension system said it had been served with a grand jury subpoena for documents. They have said nothing about Tuesday’s revelation by state Treasurer Stacy Garrity that federal subpoenas were served on “several PSERS management officials.”