WASHINGTON – FBI agents have searched the home of former Iowa state Sen. Kent Sorenson, once a top official in U.S. Rep. Michele Bachmann's 2012 presidential campaign, his lawyer said Wednesday.

The search, conducted two weeks ago, appeared to focus on communications between various campaign operatives and Sorenson, who abruptly quit as Bachmann's Iowa campaign chairman in the closing days of the Iowa Republican caucus campaign and threw his support behind Ron Paul.

"It was a very thorough federal criminal search warrant," said Des Moines attorney Ted Sporer, who represents Sorenson. "It's pretty obvious they are looking for communications with a presidential campaign or third parties working for a presidential campaign."

The Bachmann and Paul campaigns have come under scrutiny for allegedly making secret payments to Sorenson, who recently resigned from the Iowa Senate under an ethics cloud.

According to Sporer, agents seized computers and other materials connected to Sorenson's work with both campaigns, suggesting that the federal probe into Bachmann's campaign finances is far from over.

A person who answered Sorenson's home phone Wednesday said he was not available for comment.

The FBI field office in Omaha referred questions about the raid to the U.S. attorney's office in Iowa, which did not immediately respond. A spokesman for the Justice Department in Washington said he could provide no information.

Two former aides to the Minnesota Republican told the Star Tribune in May that they had been questioned by agents from the FBI's public integrity section. Central to the FBI inquiry were alleged payments to Sorenson.

But recent allegations of payments by Paul operatives appear to have broadened the scope of the federal inquiry.

"It's hard to unravel," Sporer said. "I don't know if it's a series of related investigations, or if it's one big investigation or multiple unrelated investigations. My gut instinct is it's one investigation."

'Wasn't unanticipated'

Sporer said Sorenson, who now works in real estate, cooperated with agents while his wife and their home-schooled children left during the search.

"I wouldn't call it a raid," Sporer said. "It wasn't unanticipated. … It's our intention to cooperate at all stages. Obviously, we don't think Mr. Sorenson was involved in any wrongdoing."

An account of the raid was initially reported online Wednesday by libertarian economist Robert Wenzel in the Economic Policy Journal. Citing two unnamed sources, Wenzel said agents spent seven hours in Sorenson's Des Moines-area home scouring through family computers.

A special investigator for the Iowa Senate Ethics Committee found "probable cause" earlier this year that Sorenson broke state rules by taking money for presidential campaign work, including a $7,500 monthly salary from Bachmann's political action committee and an uncashed $25,000 check from an operative in the Paul campaign.

Among the allegations swirling around Sorenson are reports that he could provide the Paul campaign with a pilfered list of Iowa home-school activists taken from the personal computer of Bachmann campaign staffer Barb Heki, who later reached a settlement with the Bachmann campaign for an undisclosed sum.

Bachmann initially accused Sorenson of switching allegiances for money. But she has remained publicly silent about whether he was paid for work he did on behalf of her own campaign. Neither Bachmann's campaign attorney nor her congressional office responded to requests for comment Wednesday.

Sorenson has steadfastly denied being paid by either campaign.

Multiple probes

The alleged payments now are the subject of inquiries by the FBI, the Federal Election Commission (FEC) and the House Ethics Committee.

The Star Tribune also has obtained documents indicating a federal grand jury probe of several top Bachmann campaign operatives, including Bachmann's husband, Marcus. Among the records subpoenaed by the Justice Department are financial registers of the National Fiscal Conservative (NFC) Political Action Committee, which allegedly agreed to help raise funds for a campaign mailer ahead of the Iowa caucuses.

Federal authorities also are looking into allegations of potentially illegal coordination between the Bachmann campaign and the NFC PAC, as well as with Bachmann's political action committee, MichelePAC, which reportedly paid Sorenson through Bachmann fundraiser Guy Short.

Bachmann announced last spring that she would not seek another term in Congress.

Follow Kevin Diaz on Twitter @StribDiaz.