PORTSMOUTH, N.H. — A Maine man charged with using social media to threaten to commit a shooting at a New Hampshire high school has changed his plea to guilty, court documents state.

Police charged Kyle Hendrickson, who was 25 at the time, with criminal threatening with a firearm in April. They said he posted a video with a gun outside Portsmouth High School in which he threatened to “shoot up the school.”

A federal grand jury subsequently indicted Hendrickson in September on charges of interstate threatening communications and possessing a firearm in a school zone. Hendrickson now intends to plead guilty to those charges and is due in court on Dec. 11, court records state.

Portsmouth closed all schools for a day when the threat occurred.

Hendrickson has been represented by attorney Murdoch Walker II. Walker did not return a phone call seeking comment.