A union leader federal agents detained at an immigration protest in Los Angeles last week is well-known to California’s Democratic leadership from his years of activism in and out of the Capitol.

That’s one reason so many leading Democrats jumped to his defense.

Huerta, the 58-year-old president of a statewide janitor’s union and of the Service Employees International Union California, was arrested by federal agents Friday outside a Los Angeles garment warehouse where protesters gathered to watch and oppose an apparent workplace immigration raid.

The denouncements of his arrest poured in quickly.

“David Huerta is a respected leader, a patriot, and an advocate for working people,” Gov. Gavin Newsom said in a statement. “No one should ever be harmed for witnessing government action.”

At SEIU California, Huerta, who was released Monday, leads a union with nearly 750,000 members that is a heavyweight in statewide politics. It represents a wide range of workers, from nurses and university researchers to janitors and public sector employees.

It’s a major donor to Democratic candidates; an endorsement with its purple logo is a badge of honor for some lawmakers.

The union’s recent victories include a $25 minimum wage for all workers at health care facilities.

“Everyone knows him,” said Lorena Gonzalez, leader of the California Federation of Labor Unions, a politically powerful statewide group of unions.

Huerta is also vice president of the federation’s board.

“He’s been around for a very long time in the movement. … We sounded the alarm and everybody stood up,” Gonzalez said.

Huerta’s grandparents immigrated from Mexico to work in the fields, and his father was a Teamsters union member, he has said. He’s been organizing janitors since as early as the 1990s, has led historic strikes in Los Angeles over wages and has been involved with immigration politics for just as long.

When federal authorities working then under the now-defunct Immigration and Naturalization Service swept through California’s airports in a post-9/11 crackdown on immigrant janitors and baggage handlers who were employed illegally, Huerta called for reforms that would allow more workers to get their papers.

As leader of the SEIU United Service Workers West, which represents janitors and security guards across California, he’s emphasized English classes and citizenship for members.

In 2016, his union successfully pushed for the state to pass training and stronger harassment protections for janitors, who often face sexual assault working alone on the night shift.

State Senate President Pro Tem Mike McGuire, D-North Coast, criticized Immigration and Customs Enforcement’s “fascist tactics.” U.S. Sen. Adam Schiff, D-Calif., called it “part of a larger campaign of intimidation by the White House.”

By Saturday morning, congressional Democratic leaders from around the country were criticizing the raids and calling for Huerta’s release.

Federal authorities accuse Huerta of obstructing agents, though the circumstances of his arrest remain blurry. Video posted Friday on social media by Assemblymember Isaac Bryan, D-Culver City, appears to show agents in law enforcement vests pushing Huerta to the ground as protesters cry out nearby.

Bill Essayli, U.S. attorney for the Central District of California, wrote on social media that Huerta had “deliberately obstructed” federal agents who had a judicial warrant by blocking their car. Ciaran McEvoy, spokesperson for Essayli’s office, would not share the warrant, saying only that the agents were “targeting employers and businesses believed to not be in compliance with federal immigration laws.”

The union leader was detained at the federal Metropolitan Detention Center in downtown L.A. and made an initial appearance Monday afternoon on charges of impeding a federal agent.