PORTLAND — A Portland man accused of sending threatening letters to Gov. Paul LePage and other government officials has been indicted on new charges.

A federal grand jury on Wednesday indicted Michael R. Thomas, 51, on charges of interstate stalking and making a terrorist hoax. He is accused of sending threatening and harassing letters to a person in Massachusetts over the course of almost five years and of sending a letter containing white powder to a Massachusetts address.

The grand jury also indicted Thomas on two counts of threatening a member of Congress, four counts of mailing threatening communications and possession of a firearm by a convicted felon. Thomas had previously been indicted on those charges in April.

Thomas is accused of sending threatening letters to LePage, Sen. Joseph Lieberman, I-Conn., Rep. Steve King, R-Iowa, and Wisconsin Gov. Scott Walker.

If convicted, Thomas faces a maximum of 10 years in prison for the threats to a member of Congress, firearm and interstate stalking charges. He faces a maximum of five years for the mailings to LePage and Walker and the terrorism hoax charge.

A date for his arraignment has not been set.