SAN DIEGO — Metropolitan Transit System’s acting board chair on Friday called for an independent investigation by an outside counsel in response to a former employee’s allegations against Nathan Fletcher.

Stephen Whitburn, also a City of San Diego councilmember, said in a statement that an independent investigation by a Board of Directors-commissioned outside counsel “would be appropriate” to supplement the investigation by the law firm contracted by MTS.

This comes one day after MTS said it would assign the lawsuit and investigation to the firm of Paul Plevin Quarles, which handles labor and employment matters for the agency.

“Since this matter proceeded directly to litigation, the investigation will take place as part of MTS’s response to that lawsuit,” Thursday’s statement read.

Whitburn also called for a special closed-door meeting of the MTS Board of Directors next week to “discuss the allegations” and to “provide direction as the Board may deem appropriate.” The board will set a day and time on Monday.

Fletcher, San Diego County supervisor and former MTS board chair, is facing allegations of sexual assault and battery by Grecia Figueroa, a former MTS public relations specialist.

Fletcher first announced the potential lawsuit in a statement Wednesday, saying that he had “consensual interactions” with a former colleague and that individual had filed a lawsuit for several million dollars against him and his wife, former Assemblywoman Lorena Gonzalez.

The complaint details two alleged instances of sexual assault by Fletcher in his role as chairman of the MTS board. MTS was also named as a defendant in the complaint, which alleges Figueroa was fired abruptly on Feb. 6 – the same day that Fletcher announced his campaign for the California State Senate.

Late Wednesday, Fletcher announced he would be resigning from the Board of Supervisors effective May 15. He had quietly resigned as MTS board chair the previous day.

On Sunday, Fletcher announced he would be suspending his campaign for state Senate to seek treatment for substance abuse and post-traumatic stress.

FOX 5’s Danielle Dawson contributed to this report.