Democrat Abigail Spanberger apologized to Rep. Dave Brat, R-Va., on Monday for an offensive missive left on the doorstep of his residence by a campaign volunteer.

Spanberger campaign manager Dana Bye confirmed that four high-school students who were volunteering for the campaign and canvassing near Brat's 7th Congressional District neighborhood hand-wrote "Rot in hell Dave" on official Spanberger campaign literature and left it on the congressman's doorstep. Bye said the individuals have been told they are no longer welcomed by the Spanberger campaign.

"This type of behavior is completely unacceptable and beneath the dignity of this race, and we have already notified these students that they are not welcome to volunteer with our campaign again," Bye said in a statement. "We apologize to Mr. Brat and his family."

Campaign staff and volunteers that conduct voter turnout operations are usually provided maps that include which streets and houses to canvass, and the Spanberger campaign told the Washington Examiner that Brat's residence was knowlingly and purposely left off of the canvassing list provided to the four volunteers who left the offensive note — as it is to all volunteers who might be reaching out to potential voters near the congressman's home.

Spanberger, a former clandestine officer for the CIA, has made inroads in the suburban Richmond 7th District, a Republican-leaning seat that Brat won in 2014 after he ousted Eric Cantor, then the GOP House majority leader, in a primary.

As with Republicans in other suburban districts in a midterm election shaping up as a backlash against President Trump, Brat is in trouble and looking for any edge to survive. After the note from the Spanberger volunteers was discovered, the Brat campaign condemned and referred the matter to local law enforcement and the Capitol Police that protect the U.S. Capitol and members of Congress.

“Abigail Spanberger and her campaign are trying to intimidate Congressman Brat and his family in their own home. Abigail Spanberger should denounce the outrageous actions of her own team and dismiss the people involved. She should also issue an apology to the Brat family," Brat campaign spokeswoman Katey Price said in a statement. "Spanberger is claiming to run a campaign about 'civility' and at the same time her campaign is sending her team to Dave Brat’s house to intimidate his family. This is politics at its worst."

The Brat campaign statement was issued prior to the Spanberger campaign determining what had occurred. After the Democrat figured out what happened, it disavowed the actions of its volunteers, dismissed them, and issued an apology. The incident stood to damage Spanberger.

She has run against Brat, a firebrand, by vowing to reduce tensions in Washington and has complained that Republicans crossed ethical lines by using information about her past that was obtained in error from government agencies.

"As someone whose personal, confidential information has already been compromised in the course of this campaign, Abigail believes that politics should never threaten the safety and security of any candidate, their family, or their staff,” Bye said.