SACRAMENTO (CBS13/AP) — The FBI searched the offices of a California state senator on Tuesday but would not disclose the reason for the investigation.

Laura Eimiller, a spokeswoman for the FBI office in Los Angeles, said the warrants were served at about 3 p.m. Six to eight agents left the Capitol more than six hours later carrying at least a half-dozen boxes and what appeared to be a computer hard drive.

She would not disclose the target of the search warrants, but Senate Chief Sergeant-at-Arms Tony Beard told The Associated Press it was Sen. Ron Calderon, a Democrat from the Los Angeles County city of Montebello.

“It’s a federal search warrant served on Sen. Calderon’s office. It’s a sealed search warrant. I don’t know what it relates to,” Beard said.

He said Calderon was not present during the search.

Calderon did not return a message left on his cellphone. His spokesman, Rocky Rushing, said he could not comment and referred calls to Los Angeles attorney Mark Geragos.

Geragos shared his outrage at the search by the federal investigators with CBS13.

“This is a leak from the U.S. Department of Justice,” he said. “They should be ashamed of themselves.”

Beard said agents served warrants at Calderon’s office and the legislative office building at the Latino Legislative Caucus office.

He added the warrants are sealed and that the Senate will cooperate with agents in the investigation.

He said he does not know what the FBI is investigating or if others also are targets of the investigation.

He contended the Justice Department is targeting his client, a Democrat, as “a bait and switch” to mute congressional Republicans’ outcry over recent disclosures, including that the department obtained telephone records from AP reporters and editors and private emails from a Fox News correspondent.

Beard told reporters who gathered outside Calderon’s office Tuesday night that the office of the Latino Legislative Caucus, which is across the street from the Capitol in the Legislative Office Building, also was searched. A spokeswoman for the caucus, Lizette Mata, did not return telephone and email messages.

Sacramento defense attorney William Portanova entered and left the Capitol office during the search. He told the AP he was retained to represent the interests of the Senate as a whole, not any particular lawmaker.

“They’re 100 percent cooperative with any investigation,” Portanova said late Tuesday.

The warrants were being served as lawmakers who are part of the 23-member Latino caucus held an event with reporters at the Capitol to discuss the group’s legislative priorities.

Tuesday’s raid at the Capitol recalled the so-called “Shrimpscam” investigation in 1985, in which federal agents went undercover and posed as representatives of a phony shrimp-processing company. Five lawmakers went to prison for taking bribes in the FBI sting operation.

Eimiller said the current investigation is being led by federal authorities in Southern California, where Calderon is based, but the search warrants were issued in U.S. District Court in Sacramento and are under seal.

She said the search was conducted to investigate “allegations of criminal activity.”

“This is an ongoing investigation,” she said. “Searches are typically done in the early stages of an investigation, so it would be premature to say that charges will be filed.”

In 2009, the state’s political watchdog agency, the Fair Political Practices Commission, closed an investigation into Calderon’s three Assembly campaign committees without sanctions.

The commission opened an investigation after receiving allegations that Calderon had used campaign money for personal purposes while seeking re-election to the Assembly in 2003 and 2004, according to agency records. A letter to Calderon said the agency found nothing on its face to show the expenses were made for “anything other than a political, legislative or governmental purpose.”

Calderon terminated his legal defense fund in 2009.

The lawmaker is part of a powerful Southern California political dynasty. His two brothers served in the state Legislature and his nephew, Ian Calderon, was elected to the Assembly last year.

He is known as a moderate, business-friendly Democrat. After his election to the Assembly in 2002, he was a member of the Assembly Moderate Caucus.

Calderon played a key role last year in brokering an agreement that led to new state laws governing foreclosures that went beyond the national mortgage settlement with the nation’s five largest banks.

He originally balked at proposals by Attorney General Kamala Harris that he thought would do too much harm to the lending industry. He then cast a key vote in an unusual conference committee that led to the compromise legislation becoming law.

He also has promoted regulatory reform and Hollywood tax credits, among legislative initiatives reflecting his business-oriented interests. Among other legislation this year, Calderon is carrying a bill that would require education officials to create lesson plans about violence in American culture as a way to respond to mass shootings.

Calderon also drew mention last year in an Associated Press story about lawmakers who sought upgrades to their state-provided vehicles shortly before buying them for personal use.

He special-ordered “2 vogue type wheel center caps” for $80 for his 2006 Cadillac, among other maintenance that cost taxpayers more than $500. Rushing, Calderon’s spokesman, said at the time that the spending was all for necessary or scheduled maintenance.

Chief Sergeant-at-Arms Tony Beard, Jr. confirmed late Wednesday morning that an office of the Legislative Latino Caucus was erroneously identified as part of the FBI raid. The identifying information was based on an outdated roster. The office had moved to a new location earlier this year.

Reports from the Associated Press contributed to this article.