(Warwick, RI)--Former Rhode Island Convention Center security chief James Demers appeared Monday before a grand jury that has been looking into the circumstances around an audit ordered by House Speaker Nick Mattiello.Demers, described as a close friend of Mattiello, had been the subject of an internal investigation at the same time the audit of the convention center was ordered.Demers had no comment for reporters yesterday as he left the Kent County Courthouse.