An 18-year-old Eliot man was arrested early Monday for allegedly posting a social media threat against a York County high school.

Eliot police say they were notified around 11:30 p.m. Sunday that a threat against Marshwood High School had been posted on Instagram by a former student. At 1:40 a.m., officers identified Robert Christian as the person who wrote the message, police said Monday.

Christian, a former student at the high school in South Berwick, was taken into custody and transported to York County Jail. He was charged with terrorizing, a Class D misdemeanor.

Christian’s bail was set at $5,000 and he was scheduled to be arraigned in court Monday afternoon.

A former student who saw the Instgram post notified school officials, who immediately alerted police, Superintendent Mary Nash said in a letter to parents. There will be an increased police presence for the next few days at MSAD 35 schools as a precaution, she said.

“Let me be clear – threatening behavior towards members of our community will not be tolerated,” Nash wrote. “The safety of our students and staff is our precious priority.”

Police did not provide any details about the threat, or say whether they believe Christian intended to follow through on the threat. Nash said the Instagram message “indicated ideation of doing harm to Marshwood High School.”

“We commend those that brought this information forward to ensure the safety of the students and community as a whole and are thankful to both the South Berwick Police Department and MSAD 35 officials for working alongside us during the investigation,” Eliot police said in a Facebook post.

The district serves students from South Berwick and Eliot.