If anyone is to blame for the 10 years it took Montgomery County authorities to build a sex-assault case against Bill Cosby, it is the 79-year-old entertainer himself, prosecutors said Tuesday.

In a new court filing, District Attorney Kevin R. Steele sought to counter claims by Cosby's lawyers that the 2004 allegations are too old to defend against, arguing that Cosby spent years fighting to keep under wraps damaging evidence - his own testimony - that ultimately helped lead to his arrest.

That testimony, sealed in a 2005 deposition, was made public by a federal judge last year and became a basis for the charges in December.

"This wealthy, celebrity defendant, armed with a cadre of high-priced lawyers, made sure that his incriminating deposition testimony remained a closely guarded secret for a decade," Steele wrote. "It is [Cosby] himself who has used the legal system to keep the deposition secret and used a scorched-earth approach to criminal justice in an attempt to delay and derail this case."

Steele's arguments were in response to a sweeping motion Cosby's lawyers filed this month in yet another attempt to persuade Montgomery County Judge Steven T. O'Neill to throw out the case, using arguments the judge previously rejected.

O'Neill has scheduled four days of hearings in November and December to settle disputes over what evidence prosecutors will be able to present to jurors at Cosby's June trial - among them a disagreement over whether they can use Cosby's testimony from the 2005 civil suit filed by accuser Andrea Constand.

In his filing, Steele noted Cosby's deposition transcript - in which the entertainer acknowledged that he had had sexual contact with Constand and that he had used drugs in encounters with other women - offered detectives evidence they did not have in 2005, when they first investigated her claims that she had been drugged and sexually assaulted at Cosby's residence in Cheltenham.

What's more, Steele said, the public release of Cosby's damning admissions prompted dozens of women to come forward with accusations that mirrored Constand's claims. Prosecutors hope to call some of them to testify against Cosby at trial.

"This new information suggested that [Cosby] had committed scores of sexual assaults over nearly half a century on a scale rarely seen or even imagined," Steele wrote.

Cosby's lawyers argue that they cannot properly defend their client against Constand's decade-old allegations and claims from other women, some of which stretch back farther. His memories are too faded and he is too blind to recognize many of his accusers, they said in their filing, which also noted several key witnesses have since died.

"If our justice system is allowed to be distorted and abandoned for Mr. Cosby, none of us are safe," a spokesman said Tuesday.

Cosby has denied sexually assaulting anyone and pleaded not guilty to three counts of aggravated indecent assault.