The Republican chairman of the House Intelligence Committee met a secret source on the White House grounds the day before he went public with hazy, charged allegations that members of Donald Trump’s transition team had been picked up by incidental collection of foreign nationals.

Rep. Devin Nunes (R-CA) on Monday confirmed to CNN that he clocked time there to view classified information in a secure area in order to “confirm what I already knew.” Nunes said he was not at the White House itself, and it’s unclear exactly what building he visited.

He later explicitly told Bloomberg’s Eli Lake that his source was an intelligence official, not a White House staffer, and that their meeting location was chosen out of convenience.

“We don’t have networked access to these kinds of reports in Congress,” Nunes said. By his account, the intelligence reports he viewed are only distributed on a system within the executive branch, so the White House grounds were the most convenient secure location that had a computer connected to that system.

Nunes has repeatedly refused to divulge the source for claims that communications involving Trump and his staffers were “incidentally collected” by U.S. intelligence agencies. Trump and his defenders have seized on Nunes’ allegations as cover for the President’s unsubstantiated claim that Trump Tower was wiretapped by his predecessor, Barack Obama.

Citing a need to protect his “sources and methods,” Nunes has offered no further comment when asked point-blank if the White House was the source for his revelations. He held a press conference Wednesday about his findings and privately briefed Trump about them, without bringing the information to the rest of his committee.

These details add new color to what was reportedly quite an unusual day for the California Republican.

According to reports from the Washington Post and the Daily Beast, on Tuesday evening, Nunes was in an Uber with a communications staffer when he received a brief phone call. He immediately hopped out of the vehicle, ditching his staffer, swapped cars, and departed, according to the reports.

Nunes pushed back on this reporting to CNN, saying “I was in a cab with staff and we dropped them off before I went to my meeting. Anything other than that is just false.”

Where exactly Nunes went after taking that call isn’t clear, but the Post reported that he did not visit the Director of National Intelligence, FBI or National Security Agency that night.

There are many secure sites outside of the White House where lawmakers may review classified information. The CIA, FBI, and several locations on Capitol Hill have SCIFs, or Sensitive Compartmented Information Facilities.