"Mr. Reiff, in response to a subpoena, appeared before a grand jury fully and completely answered all their questions for several hours," attorney Michael Weisel told media Wednesday.
Thursday officials will hear from more people with possible ties to Easley.
Those closely following the probe believe federal investigators suspect campaign donors with coastal real estate developments were give fast-track approval for environmental permits.
"We can no longer ignore what is going on," political watchdog Joe Sinsheimer said.
Sinsheimer said Governor Beverly Perdue should review the permits issued while Easley was in office.
Perdue stressed her new administration is open to the public.
"My administration has been committed to absolute transparency and accountability," she said.
ABC11 Eyewitness News will have the latest on Thursday's proceeding beginning at 5 p.m.