The war of words continued to escalate Thursday as the clock counted down to a courtroom showdown over the suspension of San Francisco Sheriff Ross Mirkarimi.

A judge Thursday issued a tentative ruling denying a motion by Mirkarimi to overturn his suspension on official misconduct charges.

The tentative ruling by San Francisco Superior Court Judge Harold Kahn comes in advance of a hearing Friday on the motion by Mirkarimi, 50, who was suspended without pay last month by Mayor Ed Lee.

Mirkarimi is awaiting a hearing by the city's Ethics Commission on the official misconduct charges on Monday. The commission will then make a recommendation to the Board of Supervisors, which will make the ultimate decision on whether to remove him from office.

The alleged misconduct stems from a Dec. 31 domestic violence incident in which Mirkarimi grabbed the arm of his wife during an argument, causing a bruise.

He pleaded guilty last month to a misdemeanor charge of false imprisonment and was sentenced to three years' probation and other penalties. Lee then suspended Mirkarimi on March 21.

Mirkarimi's attorneys filed a petition for a writ to overturn the suspension, arguing that the definition of official misconduct was unconstitutionally vague and that the misconduct had to have occurred while the official was in office.

Mirkarimi was still a member of the Board of Supervisors at the time of the incident and was not sworn in as sheriff until Jan. 8.

The city attorney's office filed a response brief deriding that argument, saying it would give elected officials immunity to commit crimes in the time before they were sworn into office.

Kahn's tentative ruling sided with the city attorney.

He wrote that Mirkarimi's arguments for reinstatement "can and should be addressed in the first instance by the Ethics Commission and Board of Supervisors."

The judge also ruled that Mirkarimi's suspension should remain without pay, citing a 1935 case involving the city of Vallejo.

Mirkarimi's attorney Shepard Kopp declined comment on the tentative ruling this afternoon, saying he wanted to wait to speak until after Friday's hearing.

The ruling comes after Kahn ruled against Mirkarimi on a separate issue in the case earlier Thursday.

Mirkarimi's attorneys had filed a motion to remove the city attorney's office from the suspension proceedings, saying it had a conflict of interest because, at the time, it was representing the mayor and also advising the Ethics Commission on the issue.

The city attorney's office filed a response noting that the Ethics Commission last week announced it was retaining outside counsel on the matter so the conflict issue was moot.

At a hearing this morning, the judge agreed and allowed the city attorney's office to continue to represent the mayor in the case.

Deputy City Attorney Sherri Kaiser said outside of court following Thursday's hearing that "it's understandable that (Mirkarimi) is trying to thwart the proceeedings."

"There are real reasons why the mayor brought charges. I think he is in danger… in serious jeopardy of removal. Of course, it serves him to try to short circuit the process from the outset," Kaiser said.

"I think there are very serious issues regarding Sheriff Mirkarimi’s conduct that he is going to have to answer for before the ethics commission and the Board of Supervisors," Kaiser continued.

When asked about Mirkarimi's public comments on the case, Kaiser was dismissive.

"We don't think that the explanations being given right now are particularly creditable," she said.

Mirkarimi's attorney Shepard Kopp left little doubt how he felt in his response.

"It [the suspension] is a travesty," Kopp said. "[It's a] gross over-reaching by the mayor – an abuse of the power to remove elected officials. You know when this charter provision was enacted that lets the mayor remove public officials for misconduct it was never intended to apply to this kind of situation. It supposed to apply to official misconduct which occurs while you are in office and typically related to some sort of corruption or fraud."