FIRST ON FOX: Sen. Tom Cotton, R-Ark., wants to know how the Department of Defense (DOD) allowed a U.S. airman — who set himself on fire outside the Israeli embassy in Washington, D.C., on Monday — to serve as an active duty member since 2020.

Aaron Bushnell, 25, who was an Air Force member from Whitman, Massachusetts, lit himself on fire as a protest against Israel defending itself against Hamas terrorists following the Oct. 7 attacks. Bushnell livestreamed from his Twitch account, declaring as he approached the embassy that he "will no longer be complicit in genocide," a source told The Associated Press.

Cotton wants to know how Bushnell flew under the DOD's radar, and whether he had any access to classified information that could compromise U.S. national security.

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Cotton and Bushnell

Sen. Tom Cotton, R-Ark., left, and Aaron Bushnell. (Tom Williams/CQ-Roll Call, Inc via Getty Images | Getty Images/X)

"You have made it a top priority to address ‘extremism’ amongst our total force, and this act of horrific violence — in support of a terrorist group — raises serious questions about how this individual was allowed to serve on active duty," Cotton wrote to Defense Secretary Lloyd Austin on Wednesday. 

By March 7, Cotton wants the DOD to provide information on whether Bushnell exhibited any "extremist leanings," as well as if the DOD's anti-extremism training includes addressing support for Islamic militant groups like Hamas. 

Cotton, a member of the Armed Services Committee, also wants to know if Bushnell displayed "any concerning behavior" before the incident, and if any actions were taken to address it. He's also probing whether any other military members engaged in anti-Israeli actions, violating DOD policy on restricted political activities.

The livestream of Bushnell was removed from Twitch, but officials investigating the death believe he placed his phone on the ground and poured a liquid over himself before setting himself on fire. 

In a statement on Monday, the Air Force announced Bushnell died as a result of the act. 

PENTAGON SAYS ACTIONS OF US AIRMAN WHO SET HIMSELF ON FIRE OUTSIDE ISRAELI EMBASSY IN DC WAS 'TRAGIC EVENT'

U.S. Secretary of Defense Lloyd Austin in Israel

Secretary of Defense Lloyd Austin. (Reuters/Violeta Santos Moura)

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"When a tragedy like this occurs, every member of the Air Force feels it," U.S. Air Force Col. Celina Noyes, 70th Intelligence, Surveillance, Reconnaissance Wing commander said in a statement. "We extend our deepest sympathies to the family and friends of Senior Airman Bushnell. Our thoughts and prayers are with them, and we ask that you respect their privacy during this difficult time."

The Air Force said Bushnell was a cyber defense operations specialist with the 531st Intelligence Support Squadron at Joint Base San Antonio.

Fox News Digital reached out to the DOD for comment.