Here are the 4 inspectors general ousted by the Trump administration

The Trump administration has ousted watchdogs at multiple federal agencies over the past six weeks.

The moves have brought criticism from top Democratic lawmakers -- and some Republicans. Last week, lawmakers on both sides of the aisle called for a full explanation into the administration's firings.

The president has constitutional authority to remove presidentially appointed inspectors general, but he must notify Congress 30 days before doing so -- three of the four dismissals were late-night firings on a Friday.

Here's a little bit about each of the inspectors general.

May 15: Steve Linick, State Department

The most recent ouster by the Trump administration is Steve Linick, who was acting as the State Department inspector general. The announcement drew ire from top Democrats and some Republicans, who have opened an investigation.

Linick had opened an investigation looking whether Secretary of State Mike Pompeo had misused staff for personal errands, including dog walking and picking up dry cleaning, and was also investigating Trump's use of emergency authority to supply weapons to Saudi Arabia in 2019.

May 1: Christi Grimm, Department of Health and Human Services

Trump fired the inspector general of Health and Human Services, Christi Grimm, on May 1. According the agency, Grimm had worked for the Health and Human Services inspector general's office since 1999 but had been appointed as acting inspector general by the Trump administration in January 2020.

Her ouster followed the release of a report that identified critical shortages of medical supplies and staff as the coronavirus pandemic gripped the globe.

April 7: Glenn Fine, Defense Department

Glenn Fine was serving as the acting inspector of the Defense Department when he was removed from his post.

Fine was a long-time inspector general, serving the Justice Department for 11 years before becoming the acting inspector general at DOD in 2016. Fine had been appointed to lead a committee overseeing the use of $2 trillion in coronavirus relief funds.

April 3: Michael Atkinson, Intelligence Community

Atkinson was removed from his role as the inspector general of the Intelligence Community, the first in what became a series of firings. In his removal letter, Trump said he had no confidence in Atkinson, whom he tapped for the job in 2017.

Atkinson's communications to Congress about a whistleblower complaint helped initiate the Ukraine impeachment inquiry against the president.

ABC News' Trish Truner, Alex Mallin, Conor Finnegan and Ben Siegel contributed to this report.