Senate Minority Leader Chuck Schumer is imploring dozens of inspectors general to investigate whistleblower retaliation in the Trump administration after last week's purge of two impeachment witnesses.

The New York Democrat sent letters on Monday to 74 independent watchdogs, asking that they look into the treatment of government whistleblowers following the removal of Lt. Col. Alexander Vindman from the National Security Council and U.S. Ambassador to the European Union Gordon Sondland's sudden recall from his post.

Schumer argued that President Trump’s decision to jettison Vindman and his identical twin brother Lt. Col. Yevgeny Vindman from the White House was “part of a dangerous, growing pattern."

"Although LTC Vindman lived up to his oath to protect and defend our Constitution by bravely stepping forward to tell the truth, he has been viciously attacked by the President and forced to endure threats to his and his family’s safety," Schumer wrote. "These attacks are part of a dangerous, growing pattern of retaliation against those who report wrongdoing only to find themselves targeted by the President and subject to his wrath and vindictiveness. They also include attempts to publicly identify the anonymous whistleblower who used the proper legal channels to initially report the President’s attempts to compromise our national security for his personal benefit."

Schumer said, "The retaliation against LTC Vindman, the anonymous whistleblower, and others like them shameful, it is also illegal."

During the impeachment inquiry, the Democratic leader urged the Army secretary, the Army's chief of staff, and Defense Secretary Mark Esper to ensure that both Vindmans are protected "professionally and personally."

In his letter to the Defense Department’s acting Inspector General Glenn Fine, Schumer asked for documentation about when employees were last reminded of their protections as a whistleblower and demanded that Fine reassure Congress that future whistleblowers are protected when they come forward.

“Without the courage of whistleblowers and the role of Inspectors General, the American people may never have known how the President abused his power in the Ukraine scandal,” Schumer wrote. “It is incumbent on you that whistleblowers like LTC Vindman — and others who put their lives on the line to protect our freedoms — are protected for doing what we hope and expect those who serve our country will do when called: tell the truth.”

Trump ordered the removal of the Vindmans from the National Security Council, likely sending them back to roles within the Pentagon. Both of the brothers are still on active duty in the military. The president claimed Alexander Vindman, who was an impeachment witness against Trump, had “problems with judgment” and needed to be removed. In his impeachment testimony, Vindman said he was told by his superiors to stay quiet about concerns he had related to Trump’s July 25 phone call with Ukraine's president.

Details about this conversation, in which Trump pressed Ukrainian President Volodymyr Zelensky to investigate his political rivals, first appeared in a whistleblower complaint that sparked impeachment proceedings. The identity of this whistleblower, known only to be a CIA analyst, is not publicly known, but Republican allies of the president have called for this person to come forward to answer for what they claim to be a sham impeachment. Trump was acquitted of two charges in the Senate on Wednesday.