The Democratic mayors of Boston, New York City, Chicago and Denver testified Wednesday before the Republican-controlled House Oversight Committee in Washington, DC. The Congressional hearing was part of a federal investigation into so-called "sanctuary cities."

Committee Chairman James Comer, a Republican from Kentucky, launched the probe back in January to look into what he described as "the policies of sanctuary jurisdictions and their impact on public safety and federal immigration enforcement."

Comer sent letters to Mayor Wu and the mayors of New York, Chicago and Denver asking them to testify at Wednesday's hearing.

"Sanctuary cities", such as Boston, have policies against turning over undocumented immigrants who could be deported by federal agents. The cities limit cooperation between local police and federal immigration agents. Each city is now at risk of losing federal funding if they don't comply with new immigration laws.

Boston Mayor Michelle Wu's opening statement

"When it comes to criminal matters, the Boston Police partner every day with state and federal law enforcement," Wu told the panel in her opening statement. "But Massachusetts State law and the Boston Trust Act make clear that immigration is federal law enforcement's responsibility."

"We are the safest major city in the country, because our gun laws are the strongest in the nation, because our officers have built relationships over decades, and because all of our residents can trust that they when they call 911 in the event of an emergency or to report a crime, help will come. This federal administration's approach is undermining that trust," the mayor said.

"One in four Boston residents were born somewhere else. Most have jobs; many have kids. All of them chose this country as home, because - like my mom and dad - they believed that, here, where you've been doesn't limit where you're going; the strength of your character has nothing to do with the color of your passport; and that how hard you work matters more than where you were born." 

Wu and Comer's heated exchange

Comer and Wu had a heated exchange early on in the hearing. 

Comer asked the mayor about a case where he says a man in a Boston suburb allegedly raped and impregnated his 14-year-old daughter while living in a migrant shelter. Comer asked Wu if, under Boston law, the suspect would be turned over to ICE under a detainer.

"Whenever there's a criminal warrant, Boston police enforce that and hold people accountable," Wu responded.

Comer followed up by asking "Would you turn that criminal over to ICE?"

"This happened outside of the city of Boston. But I can tell you in the city, whenever someone commits a crime, whenever there's a criminal warrant, we hold them accountable. If ICE deems they are dangerous enough to hold, obtain a criminal warrant, and Boston police will enforce it," Wu said.

Comer repeated his question again following that answer.

"We follow the laws, and make sure…" Wu began, before Comer cut her off and said, "I'll take that as a no."

Wu responds to Tom Homan "bringing hell" to Boston

Last month, President Donald Trump's "border czar" Tom Homan spoke at the Conservative Political Action Conference, issuing a warning specifically to Boston Police Commissioner Michael Cox.

"The police commissioner of Boston, you said you'd double down on not helping the law enforcement offices of ICE. I'm coming to Boston, I'm bringing hell with me," Homan said.

During Virginia Rep. Gerry Connolly's time on Wednesday, he asked Wu about Homan's remarks.

"Let's talk about Tom Homan. Shame on him for lying about my city, for having the nerve to insult our police commissioner who has overseen the safest Boston's been in anyone's lifetime," Wu responded. 

"Bring him here under oath and let's ask him some questions. I am here to make sure that the city of Boston is safe. Others may want to bring hell. We are here to bring peace to cities everywhere."

Rep. Ayanna Pressley clashes with chairman

Rep. Ayanna Pressley, a Massachusetts Democrat, attempted to introduce an article for the record to show that U.S.-born Americans commit more rapes and murders than immigrants.

As she attempted to read the information, Comer shouted over her, saying she did not have permission to speak.

"Listen, this trend of you all trying to get thrown out of committee so you can on MSNBC is going to end. We're not going to put up with it," Comer said. 

Pressley attempted to speak over Comer, saying she would be heard.

"This is my procedural right as a member of this committee to enter documents into the record. I am reclaiming my time," she said, while Comer was still attempting to stop her. "You do not get to dictate how I recite articles for the record and I take particular Umbridge as a survivor as sexual violence, I will enter into the record, this is my right. Thank you."

Rep. Stephen Lynch questions mayors

Massachusetts has two representatives on the House Oversight Committee - Congressman Stephen Lynch and Congresswoman Ayanna Pressley.

Lynch said President Trump won the 2024 election largely on the issue of immigration.

"The current president of the United States, Donald Trump, rode into office on this issue. He put people in fear," Lynch said. "So the costs to democracy are massive. It Is now threatening our democracy because we mishandled this issue. So we need to get together on this and turn immigration into the biggest blessing that this country has, and not something that people are afraid of."

Lynch asked the mayors how lawmakers can balance immigration policy with the so-called "sanctuary city" laws.   

Responding to her fellow Massachusetts politician, Wu said, "Please, pass comprehensive immigration law that is consistent and compassionate. That will make our jobs possible and we would so appreciate that partnership."

"Sanctuary city" hearing concludes

The final question Wu was asked was if there is a "reasonable limit" of immigrants Boston would welcome before the city would be considered "overrun."

"Respectfully, I'm the mayor of Boston. I don't get to decide who comes into our country and where they go after that," Wu said. "Our job is to keep people fed, and healthy, and safe when they arrive in our city. And we do that in order to make sure that everyone across our community is safe. Resources are strained. And I would ask you to please do your job and be part of passing bipartisanship legislation that would allow us to do what we want to do."

A short time later, Comer ended the hearing on a lighter note.

"That's it. In closing, I want to thank our witnesses for being here today. Believe it or not, this is the best behaved this committee's been all Congress," he said.

Boston immigration rallies

While Wu and her fellow mayors were testifying, dozens of people held dueling rallies outside Boston City Hall Wednesday morning.

The organizers of one of the groups said they were gathering in support of enforcing immigration laws, saying sanctuary cities "put illegal immigrants before citizens."

The other group described its rally as a standout in solidarity with immigrant communities.

The overwhelming majority of rallygoers were in support of Mayor Wu, holding signs that read "We've Got Your Back."  

"All of us are immigrants. The rhetoric has been going on for too long blaming problems on immigrants – legal or illegal," Suzanne Lee of the Chinese Progressive Association said.

They attempted to drown out the smaller crowd of people who were calling for an end to the city's sanctuary city policies.

"If people want to come to this country – they should do it legally. If somebody is here illegally, they're breaking the law, and we should treat it like any other crime," Catherine Vitale said.

As the crowds got bigger, Boston Police officers could be seen forming a barricade between rallygoers and the stage.

"This is what it looks like to keep on keeping on. I want to thank Mayor Wu for having the courage to travel to DC and fight for our people," Boston City Councilor Julia Mejia said.

Wu, a Democrat, prepared for her testimony before Congress for weeks. WBZ-TV has learned the mayor's office paid an outside law firm, Cahill Gordon & Reindel, $650,000 to help Wu get ready.