Two European men who allegedly carried a “swatting” campaign targeting U.S. lawmakers and others were responsible for the attack on the head of the Cybersecurity and Infrastructure Security Agency last year.

Recorded Future News has confirmed that Thomasz Szabo, 26, of Romania, and Nemanja Radovanovic, 21, of Serbia — who targeted roughly 100 individuals with calls intended to provoke an aggressive response by law enforcement at the home of the victim — were behind the swatting attack on CISA Director Jen Easterly last December.

A federal indictment against the two men was unsealed last week. The pair are charged with conspiracy and more than two dozen counts of making threats over the span of more than three years. 

In addition to Easterly, the duo targeted a former U.S. president, members of Congress and senior federal law enforcement officials.

In Easterly’s case, police in Arlington County, Virginia, said they investigated a 911 call placed around 9 p.m. on December 30 that claimed a shooting had occurred inside a residence on the block where Easterly lives. 

CISA confirmed at the time that the hoax call was directed at Easterly's home and that she was alone.

“While my own experience was certainly harrowing, it was unfortunately not unique. In particular, several of our nation’s election officials have also been targeted with this type of harassment and other threats of violence,” Easterly said in a statement.

Last week’s federal indictment states almost 20 attacks took place on the same date. Neither that document, or the supporting affidavit, identify Eastely by name. Recorded Future News confirmed she was among the victims through two sources with knowledge of the development and who were granted anonymity due to the sensitivity of the matter.

A CISA spokesperson declined to comment.

Matthew Graves, the U.S. attorney for the District of Columbia, whose office brought the charges, said in a statement that swatting “is not a victimless prank — it endangers real people, wastes precious police resources, and inflicts significant emotional trauma.”

“We will use every tool at our disposal to find the perpetrators and hold them accountable, no matter where they might be.”