During an hour of questioning, San Francisco's sheriff admitted to an ethics panel weighing his fitness for office Thursday night that he grabbed his wife's arm several months ago and caused a large bruise.

Ross Mirkarimi was suspended without pay in March by Mayor Ed Lee after the sheriff pleaded guilty to a misdemeanor domestic violence charge in the incident involving his wife.

The mayor is seeking to permanently remove Mirkarimi from office.

Under meticulous questioning by Deputy City Attorney Peter Keith, Mirkarimi acknowledged that he had grabbed the arm of his wife, Eliana Lopez.

"I reacted intensely to a quarrel and I was wrong in the way I reacted," Mirkarimi said.  He said that the action caused a large bruise on her arm.

Mirkarimi was sworn as sheriff in January after winning election in November. He previously served seven years on the Board of Supervisors.

Mirkarimi's woes began on the afternoon of Dec. 31 when he and his wife became involved in an argument over whether she could travel to her native Venezuela with their three-year-old son.

Mirkarimi admitted bruising her arm with an overly firm grip. He pleaded guilty to misdemeanor false imprisonment in exchange for the dropping of other misdemeanor charges. He was sentenced to probation and counseling.

Lopez and her son departed for Venezuela March 25 and have not returned. A judge has given Mirkarimi permission to visit his son, but he still under a court-order to stay away from Lopez.

The hearing in front of the five-member commission set to resume Friday morning, with Mirkarimi scheduled to return to the stand.  Mayor Ed Lee is also scheduled to testify.

The commission opened its inquiry into Mirkarimi's fitness for office last week. The panel will forward its recommendation to the Board of Supervisors.

This is the first time the panel has convened a trial-like hearing to determine whether an elected official should be removed from office. It will forward its recommendation to the Board of Supervisors, which needs the votes of nine of 11 members to remove Mirkarimi. The mayor and his lawyers are asking for a removal recommendation.