(Providence, RI)--WPRI-TV reports a statewide grand jury is actively investigating part of Rhode Island House Speaker Nick Mattiello's 2016 re-election campaign.Sources tell the news station the jury is probing the endorsement of Mattiello in a mailer by his original Republican opponent, Shawna Lawton.An investigation from the Board of Elections found two Mattiello aides were involved in paying for and distributing the mailer, even though it was reported as an independent expenditure.