BALTIMORE — FBI and IRS agents raided the homes and offices of Baltimore’s embattled mayor on Thursday amid widening probes to determine whether she used sales of her children’s books to disguise government kickbacks.

Dave Fitz, an FBI spokesman in the agency’s Baltimore office, said agents with the FBI and the IRS criminal division in Washington were searching both of Mayor Catherine Pugh’s homes and her offices at City Hall, as well the home of a top aide and other places. He said he couldn’t release more information because the warrants are sealed.

Pugh has been facing mounting calls for her to resign over a scandal involving her self-published children’s books, which she sold to a health plan that does business with the city, as well as to the University of Maryland Medical System, on whose board she sat while serving as a state lawmaker. Pugh sold $500,000 worth of the books to the $4 billion hospital network over the years, and meanwhile pushed legislation that would have benefited the regional system.

The federal case comes amid a criminal investigation by the state prosecutor’s office, which began at the request of Republican Gov. Larry Hogan, as well as probes by the Baltimore Inspector General, a city ethics board and the state insurance commission.

As federal agents gathered boxes of evidence in the mayor’s office and police cordoned off her homes with yellow tape, City Council member Brandon Scott called the raids “an embarrassment to the city.”

“The mayor should resign. We have too many issues facing the city of Baltimore that require the full-time attention of a full-time mayor,” Scott said.

Pugh’s spokesman, James Bentley, said Thursday that he hadn’t spoken with the mayor and doesn’t know where she is. Her defense attorney, Steve Silverman, did not immediately return calls; his office routed calls to an answering machine. Yellow police tape surrounded her home as agents searched inside.

City Solicitor Andre Davis said City Hall is cooperating fully with federal investigators.

It’s been more than three weeks since Pugh slipped out of sight, citing deteriorating health from a pneumonia bout. Six of her staffers joined her on paid leave; on Wednesday, the acting mayor fired three of them.

Pugh said she was going on leave on the same day Hogan asked for the investigation of her “Healthy Holly” book sales, which earned about $800,000 for her limited liability company.

Since then, the first-term mayor has been asked to resign by the entire lineup of the current City Council, all Baltimore lawmakers in Maryland’s House of Delegates, the influential Greater Baltimore Committee business group and others. Maryland’s chief accountant called Pugh’s “self-dealing” arrangements to sell her books as “brazen, cartoonish corruption.”

But only a conviction can trigger a Baltimore mayor’s removal from office, according to City Solicitor Andre Davis and the state constitution. Baltimore’s mayor-friendly City Charter currently provides no options for ousting its executive.

“The charter is utterly silent on how long the leave can last, exactly what the reasons are for a leave,” Davis told reporters.

Members of Pugh’s communications staff have said repeatedly that she intends to return to City Hall when she is feeling better, but have declined to provide any timetable.

With the investigations intensifying, political analysts said Pugh’s biggest bargaining chip is her refusal to resign in a city accustomed to a high-drama, insular political culture.

Pugh came to office in late 2016 after edging out ex-Mayor Sheila Dixon, who spent much of her tenure fighting corruption charges before being forced to depart office in 2010 as part of a plea deal connected to the misappropriation of about $500 in gift cards meant for needy families.

While the accusations have certainly cast a shadow over Pugh, she has not been indicted for any crime, and it is unclear how long a criminal investigation will take. Earlier this month, Silverman said the mayor looks forward to cooperating with the state prosecutor’s probe and will provide “as much information as possible to put this matter to rest.”

Pugh would certainly face a bruising 2020 Democratic primary if she were to return and run for reelection. Many political observers believe she’ll never again be able to wield power effectively due to the scandal.

A veteran City Council leader, Bernard “Jack” Young, is serving as acting mayor. Young said he would merely be a placeholder when she went on leave, and stressed that the decision is up to her. But given the groundswell of opinion against her, he said “it could be devastating for her” if she tried to return.