Bill Cosby faced his first hearing on a sexual assault charge in a Montgomery, Pennsylvania, courthouse on Tuesday, in hopes of getting the case dismissed.

Outside the courthouse, Cosby held on to two assistants for support and clutched a cane. The 78-year-old comedian filed court documents claiming he is "legally and functionally blind."

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Inside, former Montgomery County District Attorney Bruce Castor was the first witness Cosby's legal team called to the stand where he explained why he didn't bring criminal charges against Cosby in 2005 with regard to former Temple University employee Andrea Constand's claims of sexual assault.

According to Castor, Constand's actions -- including contacting a lawyer before going to police -- didn't reflect those of a sexual assault victim and "created a credibility issue."

Castor claims he made an oral agreement with Cosby that he would not criminally prosecute him on the case stemming from Constand's accusations.

The prosecutor, Montgomery County District Attorney Kevin Steele, argues that an oral immunity deal is irrelevant. According to Steele, any such deal should have been written down and agreed to by a judge.

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Cosby was charged in December for the alleged incident that is said to have taken place in January 2004. Constand alleges that Cosby drugged and violated her at his mansion in Elkins Park, Pennsylvania more than a decade ago. Cosby has denied any wrongdoing.

Following Cosby's arraignment, his lawyer, Monique Pressley, appeared on the Today show via satellite to discuss the criminal charge, and said her client was "not guilty."

"My client is not guilty," Pressley told Today co-host Savannah Guthrie. "And there will be no consideration on our part of any sort of [plea] arrangement."

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The hearing is set to continue into Wednesday, with the charge carrying a maximum penalty of 5-10 years in prison and a $25,000 fine.