
PHILADELPHIA (WPVI) -- A former district attorney who decided not to charge Bill Cosby in a 2004 sexual assault case says he believes his decision is binding on his successors and closed the door on future prosecution.
Former Montgomery County District Attorney Bruce L. Castor Jr. testified Tuesday for defense lawyers who want a judge to dismiss a felony case against Cosby.
Cosby, 78, is charged with drugging and violating Andrea Constand, a former Temple University athletic department employee, at his suburban Philadelphia mansion.
Castor maintains that by publicly announcing that he wasn't going to prosecute, it took away Cosby's right to invoke his Fifth Amendment right against self-incrimination.
Castor believed by doing that Constand could get some measure of justice in civil court.
Castor said "Cosby would've had to have been nuts" to say what he did in a 2005 deposition unless he knew he was immune from prosecution.
Cosby admitted in the deposition that he had affairs with young models and actresses, that he obtained Quaaludes to give to women he wanted to have sex with and that he gave Constand three pills at his home. He said he reached into her pants in what he insisted was consensual contact.
Current D.A. Kevin Steele said Cosby would have needed an immunity agreement to avoid prosecution. Cosby was arrested on December 30, just before the statute of limitations would have expired.

Also on Tuesday, Castor said he saw the accuser's yearlong delay in reporting the incident and her contact with a lawyer before going to police as red flags.
He also said he found inconsistencies in Constand's story.
Castor cited the lack of a prompt complaint, noting it took more than a year for Constand to come forward and said by then it was difficult to collect any forensic evidence.
He also said Constand contacted a civil lawyer in Philadelphia before going to police in Canada to file a report, which he felt created a credibility issue.
In a barrage of allegations that have destroyed Cosby's image as America's Dad, dozens of women have accused the former TV star of drugging and sexually assaulting them since the 1960s. But this is the only case in which he has been charged.
Cosby arrived for the hearing in Norristown in a black SUV just before 9 a.m., dressed in a tan suit and tie. Two men held his arms for support as he walked up a ramp to the Montgomery County Courthouse, and one carried Cosby's cane. The comedian chatted with his handlers while ignoring reporters' questions.