Last Wednesday, senior FBI and national intelligence officials relayed an urgent message to the White House: Information being sought by House Intelligence Committee Chairman Devin Nunes could endanger a top-secret intelligence source.

Top White House officials, with the assent of President Trump, agreed to back the decision to withhold the information. They were persuaded that turning over Justice Department documents could risk lives by potentially exposing the source, a U.S. citizen who has provided intelligence to the CIA and FBI, according to multiple people familiar with the discussion and the person’s role.

The showdown marked a rare moment of alignment between the Justice Department and Trump, who has relentlessly criticized Attorney General Jeff Sessions and other top Justice officials for the probe into Russia’s interference in the 2016 election led by special counsel Robert S. Mueller III.

But it is unclear whether Trump was alerted to a key fact — that information developed by the intelligence source had been provided to the Mueller investigation.