RICHMOND — Abigail Spanberger’s congressional campaign apologized to Rep. Dave Brat (R-Va.) and fired four campaign volunteers who left a nasty note on the congressman’s front door over the weekend.

Brat, who is in a tight race with Spanberger in Virginia’s 7th Congressional District, received a piece of his rival’s literature on his front door with the words “Rot in hell Dave” and a smiley face scrawled on it.

Brat contacted Capitol police and Henrico County police.

“Abigail Spanberger and her campaign are trying to intimidate Congressman Brat and his family in their own home,” Brat spokeswoman Katey Price said in a written statement. “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.”

Dana Bye, Spanberger’s campaign manager, said four high school students who had been knocking on doors in the area were responsible. They have been fired from the campaign, which also issued an apology to Brat and his family, Bye said in a written statement.

“Immediately upon hearing that someone had left a handwritten, negative note at Mr. Brat’s house this weekend, we questioned the volunteers who had been canvassing in the area and discovered that four high school students were involved in this incident,” she said. “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.”

The apology brought up a controversy that erupted earlier in the race, when a Republican super PAC allied with House Speaker Paul D. Ryan (R-Wis.) obtained Spanberger’s unredacted personnel file from the U.S. Postal Service. The Postal Service acknowledged it had erred by releasing the records, which included Spanberger’s Social Security number and medical history.

“We apologize to Mr. Brat and his family,” Bye said. “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.”

Brat and Spanberger, a Democrat, are in a close contest to represent a suburban-rural swath of central Virginia, a longtime GOP stronghold widely seen as within reach of Democrats in the Trump era.

Brat, a former economics professor at Randolph-Macon College, won the seat four years ago after pulling off a shocking primary upset over Rep. Eric Cantor, then the House majority leader. Despite lingering resentment from some Cantor allies, he won reelection two years later by 16 percentage points.

But he faces a strong challenge from Spanberger, a former CIA officer who has used her national security credentials to appeal to moderate Republicans and swing voters. She could benefit from antipathy toward President Trump in the district’s suburban areas.

The Cook Political Report classifies the race as a toss-up.