Senate President Stanley Rosenberg, under mounting pressure from inside and outside of the State House, will step down as the leader of the Senate for the duration of an investigation into allegations of sexual assault against his husband Bryon Hefner.

Rosenberg, in a letter that was shared with members of his leadership team at morning meeting Monday, said he intended to take a "leave of absence as your president, effective immediately" for as long as the investigation lasts.

"I believe this is in the best interests of the Senate. 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," Rosenberg wrote in the letter, which was shared with the News Service by someone who had received it.

Rosenberg asked in the letter that the Senate elect an "Acting President" in his absence.