SACRAMENTO — The controversy surrounding sexual harassment in the state Capitol deepened on Friday and threatened to ensnare one of the Legislature’s leading Democrats, Kevin de León, as questions swirled over when the Senate leader became aware of complaints against his weekday roommate.

The plot thickened after a lawyer for a fired Senate staffer told Capital Public Radio that her client and two other employees were handed termination letters in the same meeting in which they detailed inappropriate behavior by their boss, Sen. Tony Mendoza, toward a young female intern.

The attorney’s account contradicted the timeline provided Thursday by De León’s office, raising questions about what the Senate leader, who is challenging U.S. Sen. Dianne Feinstein, knew about the harassment allegations.

Mendoza, 46, repeatedly invited the 23-year-old woman to visit him at night at the Sacramento apartment he shared with De León and once invited her to spend the night at his hotel

room at a Yolo County resort, according to Micha Star Liberty, an Oakland attorney for one of the fired staffers.

Mendoza’s alleged misbehavior was first reported Thursday by the Sacramento Bee.

The three Mendoza aides reported the harassment to Senate officials several times in September before detailing their allegations in a meeting on Sept. 22 — when they were promptly fired by being handed a letter on Rules Committee letterhead bearing De León’s name, Liberty said.

“This smacks of retaliation,” the attorney told the radio station.

The secretary of the Senate, Daniel Alvarez, on Thursday painted a very different picture of events, saying that the employees were fired before the harassment complaint against Mendoza was made. He argued that there was “no connection” between the staffers’ allegations and their termination.

“Senate Rules take any allegation of inappropriate workplace behavior extremely seriously – and this is no different,” Alvarez said in a statement provided by De León’s office. “These allegations are being rigorously reviewed and investigated consistent with our legal process, employment standards and privacy protections – and has been for months.”

Mendoza said on Thursday that he would never knowingly abuse his authority, but didn’t address whether he had ever invited the young intern to his apartment.

“If I ever communicated or miscommunicated anything that made an employee feel uncomfortable, I apologize,” he said in a statement issued to this news organization.

A spokesman for De León told the Associated Press Thursday that the Senate leader did not know about the allegations against Mendoza or the investigation into his colleague.

“The Senate is the employer of Senate staff, not individual members, and Senate Rules Committee has the responsibility for thoroughly investigating complaints in consultation with outside counsel,” Alvarez said in a follow-up statement on Friday night. “As the process requires, the Senate will take action once Senate Rules completes their investigation.”

Several former Senate staffers said it was the procedure in past years for the president pro tem — who also serves as chairman of the Rules Committee — to be notified right away of harassment investigations.

Kathy Dresslar, who served as chief of staff to former Senate President Pro Tem Darrell Steinberg, said Friday that her boss was always instantly made aware of all harassment allegations about his members by the Senate secretary, to whom Human Resources personnel report.

“When I worked in the pro tem’s office and the secretary of the Senate was Greg Schmidt, he would have come in and told us — and he did come in and tell us — when there was a complaint about a member,” she said. “Immediately.”

Schmidt died last year at age 69 after a brief battle with cancer.

Sara Velasco, a Rules Committee staffer in the ’90s who helped write the Senate’s sexual harassment policies, said she had no doubt that in the past, the pro tem would be aware of any probe.

“If there’s an investigation started, I’m sure he would know,” Velasco said.

But a De León spokesman said he did not know about the allegations.

Some political insiders questioned how De León could not be aware of the allegations against one of his members when the three staffers were fired.

“It’s unfathomable that someone in that position would not know what’s going on,” said Larry Gerston, political science professor emeritus at San Jose State. “It’s beyond belief. It’s beyond comprehension.”

Mendoza, a married father of four who chairs the powerful committee on Insurance, Banking and Financial Institutions, is the second state legislator in recent weeks to deal with headlines over harassment allegations. The Los Angeles Times reported last month that Assemblyman Raul Bocanegra, a San Fernando Valley Democrat who is a member of the Assembly’s leadership team, was secretly disciplined after he was accused of groping a female staff member at an after-work event in 2009 when he was a legislative staffer.

Attention on sexual harassment in the Capitol has sharply intensified since more than 100 female staffers, elected officials and lobbyists wrote an open letter last month decrying what they called a culture of harassment in the statehouse.

De León has publicly condemned sexual harassment and hired a law firm to conduct an independent investigation into allegations.

Political analysts say that even the appearance of an attempted coverup could be a black mark on the Los Angeles Democrat’s campaign for U.S. Senate, which is just ramping up.

“There’s a lot riding on how he handles the fallout of this,” said Sherry Bebitch Jeffe, a senior fellow at the University of Southern California. “It’s a Pandora’s box.”

Asked whether he was worried the controversy could become an issue in the U.S. Senate race, De León’s campaign spokesman, Roger Salazar, said in an email Friday night that “it is disheartening to see such a serious issue be manipulated for political purposes​.”​

He described ​De León as a “tireless champion for gender equity” who was “working with his colleagues to demand greater workplace protections for Senate employees.”

Salazar said that​ he wasn’t surprised that the candidate’s opponents would use “every dirty trick in the book” against him, adding, “one would hope that Feinstein’s supporters would reject any blatant politicization of sexual harassment.”

But Bebitch Jeffe said the simple fact that De León rooms with a senator accused of harassment will be hard to ignore.

Voters will wonder, “What did they do in the apartment?” she predicted. “Did they put a sock on the door?”