The Cosby Show star has been fighting off decades-old accusations from more than 50 women, who have come forward with claims of inappropriate behaviour, drugging and rape against the actor.

Among them is former Temple University employee Andrea Constand, who filed a civil lawsuit against Cosby in 2005, accusing the funnyman of attacking her at his mansion in Pennsylvania in 2004.

She eventually settled with Cosby in 2006, but his deposition was made public in July (15), and in the documents, the 78 year old confessed to obtaining sedatives called Quaaludes to give to women he wanted to have sex with.

Pennsylvania authorities reopened the criminal investigation into her claims, and in late December (15), Cosby was arrested and charged with aggravated indecent assault stemming from Constand's allegations. He turned himself in to police and was arraigned in a Montgomery County courthouse before being released on $1 million (£670,000) bail.

Last week (11Jan16), Cosby's lawyers filed a motion to dismiss the indecent assault charge amid allegations a prosecutor broke a promise not to press charges over his alleged encounter with Constand, arguing the prosecutor filed the new sexual assault charge against Cosby partly because of the statements he made in that deposition.

Cosby's team asked for Montgomery County District Attorney Kevin Steele's office to be removed from the case if the charge is not dropped, and now Steele's office has fired back at the defence, with hopes to block their request for dismissal.

In a statement released on Wednesday (20Jan16), Steele says Cosby is "seeking special treatment in attempting to have pre-trial motions heard prior to a preliminary hearing, the next step in the legal process," adding that the comedian is "seeking to distract from the allegations against him by attacking the District Attorney's Office."

Steele continues: "The defendant contends that a former district attorney granted him immunity or a promise not to prosecute via a press release, despite the language contained in the press release that clearly states the decision not to prosecute in 2005 may be reconsidered. Additionally, only a judge may issue a grant of immunity, which was not done in 2005 or since."

He goes on to state that Cosby's lawyers' efforts to have Steele and his office removed from the cast is "unwarranted and a blatant attempt to pick his own prosecutor," adding, "We have been ready and remain ready to present our case in court at the preliminary hearing and are asking Judge Steven T. O'Neill to dismiss this improper motion by the defense so we are able to proceed with Mr. Cosby's preliminary hearing."

Judge O'Neill is scheduled to preside over a 2 February (16) hearing on the defense's motion to dismiss the criminal case.