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A longtime California politician who was praised for his efforts to make government more transparent and authored gun control legislation was arrested Wednesday, accused of conspiracy to deal firearms and wire fraud.

The allegations against State Sen. Leland Yee were outlined in an FBI affidavit in support of a criminal complaint against him and 25 other people. The affidavit was unsealed on Wednesday, as Yee was scheduled to appear in court.

Yee performed "official acts" in exchange for donations from undercover FBI agents, as he sought to dig himself out of a $70,000 debt incurred during a failed San Francisco mayoral bid, according to court documents.

Yee is also accused of accepting $10,000 in January 2013 from an undercover agent in exchange for his making a call to the California Department of Public Health in support of a contract under consideration with the agency.

Also named in the affidavit is Raymond Chow. Chow, who is also known as "Shrimp Boy," was the former leader of a Chinese criminal organization with ties to Hong Kong.

Chow is accused of money laundering, conspiracy to receive and transport stolen property and conspiracy to traffic contraband cigarettes.

He and Yee were arrested earlier in the day during a series of raids by the FBI in Sacramento and the San Francisco Bay Area.

Yee was released from custody shortly before 7 p.m. on a $500,000 unsecured bond. He left the federal courthouse in San Francisco without comment.

His lawyer, Paul DeMeester, said Lee plans to plead not guilty but declined to discuss the case in detail, saying it's complex. The complaint is 137 pages.

"The top priority was to get the senator released, and we were able to accomplish that," DeMeester said. "The future will hold a lot of work facing this case."

The FBI was executing numerous arrests and search warrants in the Bay Area, FBI Special Agent Michael Gimbel said outside the offices of Ghee Kung Tong, a fraternal organization in San Francisco's Chinatown that Chow reportedly headed. It was among the sites searched. Firefighters were seen going inside with a circular saw and later said they had cracked a safe.

Yee is the third Democratic senator to face charges this year. Sen. Rod Wright was convicted of perjury and voter fraud for lying about his legal residence in Los Angeles County, and Sen. Ron Calderon has been indicted on federal corruption charges. Wright and Calderon are taking a voluntary leave of absence, with pay, although Republicans have called for them to be suspended or expelled from the Legislature.

Mark Hedlund, spokesman for Senate President Pro Tem Darrell Steinberg, confirmed that the FBI searched Yee's office in the state capitol on Wednesday, but he said he had no information about the arrest.

Steinberg, D-Sacramento, said he had no comment and did not know anything about the investigation.

Officers from the California Highway Patrol and Senate sergeant-at-arms details were standing guard outside Yee's office, where a morning newspaper remained untouched.

Yee, 65, represents western San Francisco and much of San Mateo County. A spokesman for the senator, Dan Lieberman, said he had no comment, but the senator's office would release a statement in the afternoon.

He is best known publicly for his efforts to strengthen open records, government transparency and whistleblower protection laws, including legislation to close a loophole in state public records laws after the CSU Stanislaus Foundation refused to release its $75,000 speaking contract with former vice presidential candidate Sarah Palin in 2010.

Chow ran a Chinese criminal organization with ties to Hong Kong and was convicted of gun charges. But he had recently been held up as an example of successful rehabilitation and was praised for his work in the community.

Yee's arrest came as a shock to Chinese-Americans who see the senator as a pioneering leader in the community and a mainstay of San Francisco politics, said David Lee, director of the Chinese American Voters Education Committee.

"People are waiting to see what happens, and they are hoping for the best, that the charges turn out not to be true," said Lee, whose organization just held a get-out-the-vote event with Yee and other Chinese-American elected officials last week.

For his efforts to uphold the California Public Records Act, Yee was honored last week by the Northern California chapter of the Society of Professional Journalists, which awarded him its public official citation for his efforts last year to maintain the requirements of the California Public Records Act.

Yee has at times clashed with fellow Democrats for casting votes of conscience, refusing to support the Democratic budget proposal in 2011 because of its deep cuts to education, social services and education. He also opposed legislation by a fellow Democrat, Assemblyman Paul Fong of Cupertino, that banned the sale of shark fins used for Chinese shark fin soup, saying that it unfairly targeted the Chinese-American community.

A longtime California politician who is currently running for California secretary of state, Yee served in the California Senate since 2006 and his district represents both San Francisco and San Mateo County. He previously was a member of the California Assembly, and is the first Chinese American elected to the California State Senate

Yee is among three Democrats running this year for secretary of state, the office that oversees elections and campaign finance reporting. He lost a bid for mayor of San Francisco in 2011.

A man was charged last year for threatening Yee over legislation that he proposed to limit rapid reloading of assault weapons. The bill would have prohibited the use of devices that allow users to swiftly reload military-style assault weapons. Lee also authored legislation that that would have required the state to study safe storage of firearms.

Chow acknowledged in an unpublished autobiography that he ran prostitution rings in the 1980s, smuggled drugs and extorted thousands from business owners as a Chinatown gang member, KGO-TV reported two years ago.

In 1992, Chow was among more than two-dozen people indicted on racketeering charges for their alleged involvement in crimes ranging from teenage prostitution to an international drug trade mostly involving heroin.

He was later convicted of gun charges and sentenced to 25 years to life in prison. He spent 11 years in prison and was released in 2003 after he cut a deal with the government to testify against another high-ranking associate, Peter Chong. Chong was later convicted of racketeering.

But Chow told KGO-TV in a 2012 interview that he had changed and was working with at-risk children in San Francisco.

U.S. Sen. Dianne Feinstein of California issued a statement in 2012 recognizing Chow as a former offender who had become an asset to his community, the Sacramento Bee reported. Chow was also praised by San Francisco Mayor Ed Lee for his "willingness to give back to the community," the Bee reported.

Fox News' Michael Lundin and The Associated Press contributed to this report.