By Matt Friedman and Katherine Landergan

A state grand jury is looking into New Jersey’s tax incentive program and has issued at least one subpoena to the New Jersey Economic Development Authority, according to three sources.

The sources requested anonymity because of the sensitive nature of the investigation.

It’s not clear if a special grand jury was convened to look into the program or if the subpoena came from an ongoing grand jury. However, this is the first indication a grand jury is involved. The state attorney general’s office said in January that it had begun a probe into the program after a comptroller’s report cited lack of oversight and other problems.

A spokesperson for the EDA did not respond to calls and emails seeking comment. A spokesperson for the attorney general’s office said only that the office will neither confirm nor deny investigations.