A still frame photo shows Border Patrol chief Gregory Bovino toss a canister of tear gas at anti-immigration enforcement protesters in Chicago on Oct. 23. Attorneys critical of Bovino say he was violating court orders limiting federal agents' use chemical weapons.
An edition of the Chicago Sun-Times shows a photo of a federal agent pointing a weapon at an unarmed teen. The photo by staff photographer Anthony Vazquez has become a symbol in Chicago of the kind of intimidation residents say they feel from agents.

CHICAGO – A judge ordered the head of President Donald Trump’s Operation Midway Blitz to answer questions Oct. 28 about whether federal agents are defying her orders to limit use of chemical weapons on protesters.

U.S. District Judge Sara L. Ellis ordered U.S. Customs and Border Patrol’s Commander at-Large Gregory Bovino to the federal courthouse in downtown Chicago after a video taken by an anti-immigration protester and linked to in court filings shows tear gas being used on protesters. The video comes amid a federal lawsuit in the Northern District of Illinois alleging immigration agents use chemical weapons unnecessarily on journalists, protesters and clergy.

Attorneys representing the group of civilians filed a notice on Oct. 26 saying that the video shows Bovino violated a temporary restraining order. Ellis is the judge presiding over the case and she issued the order, limiting agents’ use of chemical weapons to situations where officers face an "immediate threat" and compelling them to give warnings.

Homeland Security officials defend the use of chemical weapons and other crowd control tactics in the face of what they have called "rioters."

"DHS can think of nobody better to correct Judge Ellis’s deep misconceptions about its mission, and we thank him for his service," a Homeland Security spokesperson said of Bovino being called to testify.

The hearing slated for 10 a.m. local time at the Dirksen federal courthouse comes as the Supreme Court weighs whether to let the White House deploy the military to the city. The Trump administration says troops are needed to carry out an immigration enforcement crackdown aimed at the "worst of the worst" criminal immigrants.

Local Democratic officials view the blitz as a power grab from the Republican White House and have taken issue with federal agents using chemical weapons on residential streets during enforcement raids.

On Oct. 27, Homeland Security Assistant Secretary for Public Affairs said over "3,000 illegal aliens, including rapists, murderers, and gang members" have been arrested in connection with the blitz. USA TODAY has not been able to independently verify the criminal background or immigration status of detainees.

Here’s what to know before Bovino takes the stand.

Were protesters gassed?

The video that purports to show the Border Patrol chief tossing tear gas into a crowd of protesters was taken by an anti-immigration enforcement protester and linked to in federal court documents from attorneys critical of Homeland Security. The incident dates back to Oct. 23 amid an immigration enforcement raid on Little Village, a South Side neighborhood and the heart of Chicago’s Mexican community. The raid was the second in as many days.

Tear gas severely irritates the eyes, nose and throat, making it difficult to see and breathe.

According to an Oct. 26 court filing from attorneys representing the civilian groups, Bovino threw a second canister shortly afterwards "without any apparent justification or warning."

There are "significant concerns that Defendants are simply ignoring the Court’s" temporary restraining order, attorneys for the protesters, journalists and clergy wrote.

Homeland Security said then in a post on X that "rioters… began throwing rocks and other objects at agents, including one that struck Chief Greg Bovino in the head."

Later on Oct. 23 in an interview with Spanish language television station Telemundo, Bovino appears uninjured and says of Ellis’ orders, "Did Judge Ellis get hit in the head by a rock like I did this morning… Maybe she needs to see what that’s like before she gives an order like that."

Who is Bovino?

Border Patrol chief Bovino arrived in Chicago shortly after Trump launched the blitz on Sept. 8.

"Operation At Large is here to continue the mission we started in Los Angeles—to make the city safer by targeting and arresting criminal illegal aliens," he announced on Sept. 16.

The longtime Border Patrol officer directed immigration raids in LA that spurred widespread protest and quickly gained a reputation for attention-grabbing tactics in Chicago.

On Sept. 30, he directed a raid that saw agents rappelling from Black Hawk helicopters to storm a South Side apartment building. National Immigrant Justice Center attorneys say it’s unclear whether agents had warrants to conduct the pre-dawn raid that saw dozens arrested and left the building a wreck.

At about the same time, Bovino was also seen on the Chicago River aboard a boat with heavily armed agents. "TO THE BOATS," he wrote in a Sept. 30 post on X. "We will use every resource and tactic to put those who violate our laws on notice that we are coming for you!"

Why did the judge try barring agents’ use of chemical weapons?

Bovino is being called to testify in connection with a federal lawsuit over federal immigration agents' use of chemical weapons on journalists, clergy and protesters.

The lawsuit was first filed in the Northern District of Illinois on Oct. 6 and Ellis, the presiding judge, issued an order on Oct. 9 limiting agents’ reliance on aggressive tactics.

In court filings and hearings, Ellis has questioned whether agents are following her orders. On Oct. 16, she also ordered agents to use body-worn cameras following a pair of high-profile raids.

On Oct. 20, she called in top Homeland Security officials to testify. Customs and Border Protection Deputy Incident Cmdr. Kyle Harvick and Deputy Immigration and Customs Enforcement Field Office Director Shawn Byers both told Ellis that agents were following her orders.

At the Oct. 20 hearing, Ellis allowed the lawyers for the civilian group to depose Bovino for two hours. After the video of him throwing tear gas surfaced, she quickly expanded his deposition time to five hours and ordered him to appear in court, according to court filings.

Bovino’s hearing is expected to begin at 10 a.m. local time. It’s unclear if he will use the public entrance to the building or a private entrance that other immigration enforcement officials have used.

This article originally appeared on USA TODAY: Fed judge orders face of Midway Blitz to testify. Who's behind Trump's Chicago crackdown?

Reporting by Michael Loria, USA TODAY / USA TODAY

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