Congressional investigators expanded their inquiry Monday of political interference at the Centers for Disease Control and Prevention under President Donald Trump, citing newly obtained documents and additional reports of the administration’s meddling in government scientists’ work.

The expanded investigation centers on efforts to blunt the CDC’s Morbidity and Mortality Weekly Reports (MMWRs), which offer public updates on scientists’ findings. The reports had been considered sacrosanct for decades and untouchable by political appointees in the past, but Trump appointees pushed last year to edit the findings, worried that they undermined Trump’s more optimistic spin on the coronavirus pandemic.

Senior officials also discussed how to respond to a Trump appointee’s demand to edit the reports, according to a newly released email obtained by the House’s select subcommittee on the pandemic.

The subcommittee is requesting interviews with Anne Schuchat, a former CDC deputy director; Nancy Messonnier, a former senior official who held a variety of leadership roles at the CDC during the pandemic; and six current career staff members at the CDC and the Department of Health and Human Services. The subcommittee also is requesting interviews with former Trump appointees Kyle McGowan, Amanda Campbell and Nina Witkofsky, who served as top political appointees at the CDC last year.

“Our public health institutions must never again be compromised by decision-makers more concerned with politics than keeping Americans safe. It is therefore imperative that the Select Subcommittee’s investigations into the prior Administration’s response to the pandemic provide full accountings of what occurred,” Rep. James E. Clyburn (D-S.C.), the subcommittee’s chairman, and fellow Democrats wrote in their letters to HHS Secretary Xavier Becerra, CDC Director Rochelle Walensky and others.

An HHS spokesperson said the department was reviewing whether to make current staff members available for interviews and would respond directly to the subcommittee.

House Democrats also released a newly obtained email sent by a career CDC official on Aug. 9, 2020, suggesting that senior officials could meet to discuss “next steps” after then-Trump appointee Paul Alexander demanded “an immediate stop on all CDC MMWR reports.” Alexander, a deputy of then-HHS spokesman Michael Caputo, had alleged that CDC officials were deliberately working to undermine Trump with the reports, which he claimed offered an unnecessarily pessimistic view of the pandemic.

Schuchat, McGowan, Campbell and Witkofsky were copied on the email about meeting to discuss next steps; the email also was sent to former CDC director Robert Redfield. House Democrats said last year that Redfield ultimately instructed officials to delete Alexander’s email, citing an interview with a CDC official who heard the claim secondhand.

“As a member of the Office of the Director leadership team and a recipient of this email, you appear likely to have firsthand knowledge of this troubling incident, including who may have participated in relevant conversations, whether Director Redfield may have told CDC staff to delete this email, and what steps may have been taken to effectuate such an instruction,” Democrats wrote to Schuchat, McGowan, Campbell and Witkofsky.

Some of the former officials that House Democrats are hoping to interview told The Washington Post that they had no additional knowledge of how Redfield handled Alexander’s demands, including an alleged phone call between CDC officials on Aug. 9.

“We were not involved in any of those discussions,” McGowan said, noting that he and Campbell were already “out of the loop” because they had put in their two-week notice. McGowan and Campbell, who left the CDC on Aug. 14, have publicly criticized the Trump administration for interfering with CDC career officials’ work during the pandemic.

The subcommittee also released a list of 88 alleged examples of the Trump administration’s interference in public health matters last year, citing media reports and its own investigations. Some of the allegations are drawn from new books about the pandemic response and have not yet been independently verified.

Politico first reported on Sept. 11 that Trump appointees had demanded the right to edit the CDC’s reports and won some changes to scientists’ language, prompting Democrats to open an investigation. Caputo took medical leave on Sept. 16, and HHS announced that Alexander would be “permanently” leaving the agency on the same day.

Redfield and other Trump appointees repeatedly claimed last year that the agency’s reports had been protected from political interference.

“At no time has the scientific integrity of the MMWR been compromised. And I can say that under my watch, it will not be compromised,” Redfield testified to the Senate on Sept. 16. However, he told CNN in March that former HHS Secretary Alex Azar and other Trump officials tried to change several MMWRs that they did not like, a charge Azar disputed.