PORTLAND — A Portland man accused of sending threatening letters to Gov. Paul LePage, members of Congress and others pleaded guilty to several charges this morning in federal court.

Michael R. Thomas, 52, entered guilty pleas to two counts of threatening to murder a member of Congress and one count each of mailing a threatening communication, possession of a firearm by a felon and interstate stalking.

The mailing of a threatening communication charge carries a maximum penalty of five years imprisonment and the others have a maximum prison term of 10 years.

A sentencing date has not yet been set.

Thomas sent letters threatening Sen. Joseph Lieberman, I-Conn., U.S. Rep. Steve King, R-Iowa and LePage in 2010 and 2011, according to a court document filed by the prosecution.

Thomas was accused of sending at least three anonymous letters to LePage. One from January 2011 stated that Thomas did not vote for LePage.

“Now I’m ready to vote with a bullet. Yes. Thank God for our Second Amendment remedies. I’ve got you in my cross-hairs …” the letter stated

Between 2006 and 2011, Thomas also targeted a Massachusetts man with letters to his home and to others, including one that included a white substance that turned out to be baby powder, according to the document.

DNA from the letter sent to LePage was used to identify Thomas as a suspect.

In March 2011, FBI agents found a handgun at Thomas’ home at Loring House, a Portland Housing Authority property for senior citizens and the disabled. Thomas is prohibited from having guns because of a 2000 stalking conviction in Lynn, Mass.

Earlier testimony in the case portrayed Thomas as suffering from mental illness, including antisocial and paranoid disorders for which he was deemed disabled in 2002.

In court today, Thomas said he was taking medications for asthma and high-blood pressure but not any psychiatric medications.

Thomas has previously used the names Sean Higgins and Shawn Higgins.