Although Department of Homeland Security Secretary Kristjen Nielsen declared the 2018 midterms the nation’s most secure election ever, bad actors who hacked the National Republican Congressional Committee (NRCC) apparently didn’t get the message.

After one of its vendors noticed the intrusion last April, the NRCC launched an investigation and reported the incident to authorities, according to officials who spoke anonymously to Politico.

The organization, the campaign arm of the House GOP, did not notify senior members of the House like Rep. Paul Ryan, R-Wis., or other members, the report said.

“We don’t want to get into details about what was taken because it’s an ongoing investigation,” Politico quoted a senior party official as saying. “Let’s say they had access to four active accounts. I think you can draw from that.”

Allegedly, the committee was concerned that if it publicized the hack, it might be harder to find the hacker.

“The NRCC can confirm that it was the victim of a cyber intrusion by an unknown entity. The cybersecurity of the Committee’s data is paramount, and upon learning of the intrusion, the NRCC immediately launched an internal investigation and notified the FBI, which is now investigating the matter,” said Ian Prior, vice president at Mercury Public Affairs, which was hired by the RNCC to help it respond to the hack, according to the report. “To protect the integrity of that investigation, the NRCC will offer no further comment on the incident.”

Noting that since 2016 “election security has been a known critical issue” and Russian interference in the elections was confirmed in early 2017 by the House Intelligence Committee, Rep. Bennie G. Thompson, D-Miss., ranking member of the House Committee on Homeland Security, accused Republicans of having “swept the issue aside” in what he called an “age-old routine of choosing party over country.”

The NRCC “hack – which was not released for months – makes it clear Republicans ignored election security at their own peril,” said Thompson, who promised “that Democrats will continue to lead on cybersecurity and will look into all threats to our elections as soon as we take charge in January.”