House Democrats launched their first formal investigation into the Trump administration Wednesday, announcing that they will probe “grave breaches with the security clearance process at the White House and the transition team” involving senior Trump cabinet officials.

In a letter to White House Counsel Pat Cipollone, House Committee on Oversight and Reform Chairman Elijah Cummings specifically named nine current and former Trump officials, including former national security adviser Michael Flynn, senior adviser Jared Kushner, and former deputy assistant to the president Sebastian Gorka. Cummings requested a trove of documents about the Trump administration and transition team’s security clearance process.

The committee’s investigation will explore why the Trump administration appears to have “disregarded established procedures for safeguarding classified information” and the extent of classified information that was shared with people who should not have had security clearances, Cummings wrote in his letter Wednesday.

Investigators will also probe whether the White House is flouting a federal law requiring the administration to provide Congress information about its security clearance process.

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In February 2018, then-Chief of Staff John Kelly wrote in a five-page memo that there were some “shortcomings” with how the White House processed security clearances.

“Now is the time to take a hard look at the way the White House processes clearance requests,” Kelly wrote in the memo addressed to White House Counsel Don McGahn and national security adviser H. R. McMaster, both of whom have since left the administration.

Over the last two years, Cummings and other oversight committee Democrats have requested information from the White House about “extremely troubling incidents” regarding certain officials’ security clearances.

“The White House has refused to provide the information we requested, often ignoring our requests completely,” the Maryland Democrat wrote.

Nearly a year into Trump’s first term in office, more than 130 political appointees were working in the president’s executive office without a permanent security clearance, NBC reported last winter.

That figure represented roughly a quarter of all appointees in Trump’s executive office. It included Trump’s daughter Ivanka, son-in-law Jared Kushner, and McGahn, the president’s top legal counsel at the time.

In a “60 Minutes” interview earlier this month, Cummings vowed to conduct rigorous oversight over the Trump administration in a number of pressing areas.

“There’s so much [to investigate],” Cummings said. “We’ve got to hit the ground not running, but flying.”

Wednesday’s launch of the investigation into the White House’s security clearance procedures is the first of what is expected to be a slate of  Democratic House investigations into the president’s cabinet and inner circle.

House Intelligence Committee Chairman Adam Schiff has pledged to revive the investigation into the Trump’s associates’ ties with Russia.

House Judiciary Chairman Jerrold Nadler, D-N.Y., has hinted that his committee will investigate the Department of Homeland Security’s child separation policy and other immigration policy issues.