Rosenberg to step aside during investigation

The Massachusetts Senate, in the grip of its worst leadership crisis in memory, on Monday temporarily replaced its embattled president, Stanley C. Rosenberg, and set in motion a Senate investigation stemming from allegations that his husband sexually assaulted or harassed four men.

At the same time, Attorney General Maura T. Healey and Suffolk District Attorney Daniel F. Conley urged alleged victims of Rosenberg’s husband, Bryon Hefner, to come forward so they can launch a separate, criminal investigation into Hefner’s conduct.

“Sexual assault is a crime and we want to send a clear message that harassment and assault of any kind will not be tolerated,” Healey and Conley said in a joint statement.

On Beacon Hill, senators huddled behind closed doors in a marathon eight-hour meeting before publicly electing majority leader Harriette L. Chandler to serve as president until the Senate investigation concludes. Chandler, who turns 80 later this month and is a close ally of Rosenberg, pledged to relinquish the position upon the completion of the Senate’s investigation.

The chamber’s inquiry, to see if Rosenberg violated Senate rules, will be conducted by the Democrat-controlled Ethics Committee, which is poised to hire outside investigators. Senators said there was no predetermined time frame for its completion. The committee can recommend sanctions ranging from censure to expulsion or no action at all.

“The past four days have been so turbulent, so tragic, so surprising, and so sad,” Chandler, a Worcester Democrat, said in a brief speech to her colleagues, after they gave her a standing ovation on the Senate floor. “I wish I could look at this wonderful election you have given me with joy, rather than the way I feel. It truly isn’t a time of celebration for me.”

Chandler’s ascension quieted the machinations of other senators who had been angling to succeed Rosenberg on a permanent basis, but State House insiders, including Rosenberg allies, said it was unclear if the Amherst Democrat will be able to return to his leadership post. He is politically weakened and faces a cadre of ambitious candidates hoping to take the gavel.

Last week, the Globe published a report that detailed allegations by three men who said Hefner groped their genitals (two said he did so more than once) and one who said Hefner kissed him against his will.

Though three of the alleged incidents took place when Rosenberg was just feet away, the Globe found no evidence that the Senate president knew about the assaults.

Rosenberg never appeared publicly at the State House on Monday and did not attend the formal session where Chandler was elected. In a letter to his colleagues on Monday, he said he would temporarily step down as Senate president so that those making the allegations can come forward and tell their stories to Senate-hired investigators without fear. Rosenberg will remain a rank-and-file senator.

“I believe this is in the best interests of the Senate,” he wrote. “I want to ensure that the investigation is fully independent and credible, and that anyone who wishes to come forward will feel confident that there will be no retaliation.”

But one man who accused Hefner of assaulting him several times expressed skepticism Monday because Rosenberg could ultimately regain his leadership post.

“If Rosenberg is trying to come back to the Senate presidency, why should any survivor trust their investigation?” the alleged victim said.

Later Monday, Governor Charlie Baker and Lieutenant Governor Karyn Polito said they supported both Rosenberg’s decision to step aside and the prosecutors’ move to open an investigation.

“Governor Baker and Lieutenant Governor Polito believe the Senate president’s decision to step down is the right one at this time,” communications director Lizzy Guyton said in a statement. “The administration . . . urges the Senate to do everything in its power to structure an independent investigation to ensure safe reporting without fear of retribution.”

Chandler said it’s not yet clear if she will accept the higher pay, additional staff, and larger office that come with being Senate president. She said her close ties to Rosenberg shouldn’t dissuade victims from speaking to Senate-hired investigators.

“I will have nothing to do with the investigation itself. Nothing,” she said. “Somebody has got to lead the chamber. And this is acting, it’s temporary, and this is the best we can do.”

Asked if the results of the Senate investigation would be made public, Chandler said, “Absolutely.”

Rosenberg, who has served in the Legislature for more than 30 years and in 2015 became the first openly gay lawmaker elected Senate president, continues to have many supporters who are hoping he will be vindicated by the Senate investigation and return to power.

“I believe Stan has the utmost integrity and, while investigations are clearly warranted over Bryon Hefner’s interactions with lobbyists, staff, and other people in his network, it’s a separate question” whether the Senate’s official business was compromised, said Carl M. Sciortino Jr., a former state representative who is currently executive director of the AIDS Action Committee of Massachusetts.

Hefner’s alleged victims and others have said that Hefner boasted of his pull in state politics, and of his influence with Rosenberg. One alleged victim — a policy advocate who said Hefner assaulted him in the fall of 2015 — said he understood that Hefner was offering to help smooth his path in the Senate in return for sex. Several people said Hefner spoke of Rosenberg’s work in the Senate as what “we” — Rosenberg and Hefner — were trying to accomplish.

Rosenberg said last week that if Hefner made such claims, they are not true.

Though Rosenberg has not been accused of any wrongdoing, his political position ahead of his announcement Monday was precarious. At least three state senators had been calling colleagues in recent days, working to position themselves as his successor.

Senators Linda Dorcena Forry of Dorchester, Sal N. DiDomenico of Everett, and Karen E. Spilka of Ashland were said to be among those considering the powerful leadership post, should it open up.

“They [were] just sort of needling around as careful as you can,” said one Democratic senator who had received calls from Forry, DiDomenico, and Spilka. The message of the calls was effectively that “they would be candidates in the event of a vacancy. Nothing so overt as a direct challenge to Stan, though,” the senator said.

Speaking to reporters in a hallway Monday morning, Spilka parried questions about whether she had been making such telephone calls to colleagues, offering only that: “I’ve been calling people to talk about the issues.”

Forry didn’t reply to a text message. A DiDomenico spokeswoman said the senator would call back later in the day, but he didn’t.

Yet senators are bracing for new developments to come. The Ethics Committee was set to meet Tuesday morning.