BOSTON (AP) — The Senate Ethics Committee has formally opened an investigation into whether former Senate President Stan Rosenberg violated any Senate rules.

Rosenberg’s husband, Bryon Hefner, has been accused by several men of sexual assault. The Boston Globe, which first reported the allegations, said some of the men had professional business before the Legislature.

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Then-Senate President Stan Rosenberg addresses sexual assault allegations against his husband. (WBZ-TV)

The ethics panel chaired by Democratic Sen. Michael Rodrigues of Westport said Tuesday it would begin a search for an independent investigator to conduct the probe.

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The panel stressed that it would provide confidentiality to anyone who comes forward with information.

Rosenberg agreed to step aside as Senate President during the probe and Sen. Harriette Chandler, a Worcester Democrat, will replace him temporarily.

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Senate Minority Leader Bruce Tarr called for the investigator’s final report to be made public.