For decades Walter Wong has been a polarizing figure in the world of San Francisco real estate development. To some, he is a tireless self-made immigrant with an uncanny ability to usher projects through the city’s famously convoluted permitting process. To others, he is Exhibit A of an unfair system where builders who hire well-connected, expensive consultants get preferential treatment over everyone else.

The normally below-the-radar building permit consultant came under scrutiny by the FBI last week amid wire fraud allegations against Public Works Director Mohammed Nuru.

On Tuesday, FBI agents raided the 205 13th St. offices of Wong’s Jaidin Consulting Group. The raid occurred around the time charges alleging public corruption were unsealed against Nuru and restaurateur Nick Bovis.

Wong was not named in Tuesday’s federal complaint and has not been charged with a crime. He didn’t respond to requests for comment.

Wong has worked for local developers for four decades as a permit expediter, helping guide projects through the labyrinth of city approvals. He has deep ties to San Francisco politicians, including former Mayors Willie Brown, Art Agnos and the late Ed Lee. Wong was also close to the late Rose Pak, a powerful Chinatown advocate.

While developers say Wong is an indispensable figure in navigating a city bureaucracy, some community activists, city officials and residents have criticized him as being emblematic of improper influence in City Hall.

“Walter has made a living by putting his clients’ projects through the system while other people with valid, much-needed housing developments have to wait years,” said Debra Walker, who was previously on the commission that oversees the Department of Building Inspection. “It’s the culture of the department. You get special treatment if you hire certain connected people. If there are people who get special favors, there are a lot of other people who don’t.”

Officials with the Department of Building Inspection couldn’t be reached for comment.

The FBI raid, which was confirmed by a source with direct knowledge of the matter, raises new questions about Wong’s work.

City records show a connection between Wong and the Chinese developer described in the federal complaint against Nuru. A source told The Chronicle that Zhang Li, CEO of R&F Properties, is the billionaire developer who allegedly gave Nuru free hotel rooms and gifts in exchange for permitting help.

R&F affiliate Fullview Properties LLC paid Wong $72,000 in 2016 for permit work on housing projects at 325 Fremont St. and 119 Seventh St., according to a San Francisco Ethics Commission filing. The next year, R&F’s Z&L Properties division paid Wong another $24,000 for work on 325 Fremont St. Wong’s company also had contracts with the Public Works Department around Z&L’s long-delayed 555 Fulton St. project. R&F hasn’t responded to requests for comment.

Other Wong clients said he was an astute and effective advocate.

Dan Deibel, president of developer Olympic Residential Group, has hired Wong to help with projects dating to 2003, most recently at the under-construction 1028 Market St.

Deibel said Wong’s expertise is critical in getting through the city’s extremely complicated permitting process.

“It’s like going to the DMV with 10 cars (to register), and you have to go to 10 different windows,” Deibel said of getting a site plan approved in San Francisco. “It’s quite a labor-intensive process to go back and forth.”

Deibel said Wong is “effective at his job. He has a very capable staff of people that know the processes. That’s why I go back to him over and over again.”

Oz Erickson, chairman of developer Emerald Fund, has known Wong for around 20 years. Erickson hired Wong to work on permits for three Civic Center housing projects at 100 Van Ness Ave., 150 Van Ness Ave. and 101 Polk St.

“When you’re dealing with something as complicated as submitting project permits ... it’s just impossible,” Erickson said. “We wouldn’t dream of doing it ourselves. We hire the best and most efficient.”

While Wong knows his way around the Department of Building Inspection, he has also been active in city politics for years. The Chronicle reported in 2001 that Wong was a “powerhouse” who had rented office space to then-Mayor Willie Brown for his 1995 and 1999 mayoral campaigns. Brown is now a Chronicle columnist. In the next election, Wong supported and rented space to mayoral candidate Matt Gonzalez, who would lose to Gavin Newsom in 2003.

During election season, he funds a Chinese-language phone bank for his handpicked candidates, according to sources. At Original Joe’s in North Beach, Wong was a frequent dinner companion of the late Mayor Lee.

“He is a political fixer and political hanger-on,” said Supervisor Aaron Peskin, who represents Chinatown. “Presumably he is making money at it.”

The practice of expediting permits has long been criticized as an unfair system, and former city officials sought to regulate expediters in the early 2000s. Legislation was not signed until 2014. The next year, permit consultants on projects worth more than $1 million or requiring Entertainment Commission approval were required to register and disclose clients and compensation.

Wong’s disclosures show that over the past five years he was hired by real estate firms DiNapoli Capital Partners, Fisher Construction Group, Greystar, Marx Okubu Associates, TimeSpace Group and Chris Foley, owner of the Market food hall in Twitter’s headquarters building.

Before he started in real estate, Wong — who was born in 1948 in Hong Kong and immigrated to San Francisco at the age of 23 — worked as a janitor, busboy and waiter, The Chronicle previously reported. He entered the construction industry in 1979.

Former Mayor Agnos said Wong believed he was rebuffed from business jobs in the Financial District because of his Chinese accent and race, which pushed him to learn about construction and repairs, starting with fixing people’s washing machines in his truck, which evolved into building homes and becoming an expert at building codes.

“His power came from his knowledge. He was smart and skillful,” said Agnos, who met Wong in the 1980s through Rose Pak.

But Agnos said he hasn’t spoken to Wong in nearly a decade after clashing with him over the 2012 suspension of then-Sheriff Ross Mirkarimi, whom Agnos supported.

Tuesday wasn’t the first time Wong has caught the attention of federal authorities. In 2001, the FBI interviewed Department of Building Inspection staff regarding some of Wong’s projects, The Chronicle reported. No charges were filed.

Wong said at the time that if the FBI investigated him, “they would find a proud American citizen who loves his family, church, city and country.”

San Francisco Chronicle staff writer Evan Sernoffsky contributed to this report.

Roland Li and J.K. Dineen are San Francisco Chronicle staff writers. Email: roland.li@sfchronicle.com, jdineen@sfchronicle.com Twitter: @rolandlisf, @SFjkdineen