The Suffolk Police Department and Suffolk Public Schools officials are working to investigate threats against Nansemond River and Lakeland high schools.

Similar threats were made against several schools in Hampton Roads and Western Tidewater over the weekend and on Monday. In one of the threats, a message that appeared to be posted on Instagram shows a file photo of the outside of Nansemond River High School. An expletive-laced message that accompanies the photo threatens a shooting Tuesday morning.

The Instagram account no longer appears to be active.

It’s at least the third threat in three weeks for Nansemond River.

“Administrators are aware of this message and are working with Suffolk Police,” Suffolk Public Schools spokeswoman Bradshaw wrote in an email Monday afternoon. “Principal (Daniel) O’Leary will be communicating with students, staff and parents as soon as possible.”

A letter was sent out for parents and students, and the letter was also posted on the school’s Facebook page Monday afternoon.

“At 11:15 a.m. today, multiple students brought to the administration’s attention an Instagram post in which a person or persons stated they would shoot students on Tuesday,” O’Leary stated in the letter. “At this time, law enforcement and school officials in several jurisdictions, which received the same social media information, have not yet been able to authenticate its validity,” he added.

Later in the afternoon, Lakeland principal Douglas Wagoner sent out a letter addressing the threat at his school. The letter from Wagoner stated students brought a similar Instagram post to the administration’s attention that threatened various schools in the area, according to the letter.

Lakeland was not directly identified in the Instagram threat, but a “modified threat was airdropped within our school at the same time the Instagram threat was being reported,” according to Wagoner’s letter.

The Suffolk Police Department will be launching a full-scale investigation, according to both letters, and there will be a larger, proactive police presence at both schools.

“The Suffolk Police Criminal Investigations Unit is actively investigating this threat,” city spokeswoman Diana Klink wrote in a press release. “Additional police resources and staffing will be added to the schools as needed. All threats made to our schools will be thoroughly investigated and appropriate charges will be sought.”

The threats have set parents on edge following last week’s shooting at Marjory Stoneman Douglas High School in Parkland, Fla. A former student at that school reportedly opened fire on students and teachers, killing 17.