Bill Cosby lashed out Monday at seven women who have publicly accused him of sexual misconduct, saying they fabricated "malicious" and "opportunistic" allegations for financial gain.

The accusation - lodged in a countersuit he filed in federal court in Massachusetts - offers the entertainer's most forceful defense yet to claims from dozens of women, who say he assaulted them in incidents dating back decades.

It could also offer a glimpse at one potential defense strategy should Cosby face criminal charges in Montgomery County, where prosecutors are nearing a January deadline to decide whether to pursue a case against Cosby based on the decade-old allegations of a former Temple University employee.

In their court filing Monday, Cosby's attorneys accused seven of his accusers of engaging "in a campaign to assassinate Mr. Cosby's reputation and character by willfully, maliciously, and falsely accusing" him, and described their allegations of sexual assault as "nothing more than an opportunistic attempt to extract financial gain from him."

The legal battle has been brewing in Springfield, Mass., since last year. The women - Tamara Green, Therese Serignese, Linda Traitz, Louisa Moritz, Barbara Bowman, Joan Tarshis, and Angela Leslie - sued Cosby in December 2014, contending he defamed them in statements released by his attorneys denying their allegations.

Joseph Cammarata, an attorney for the women, called Cosby's countersuit a "typical page from the defense attorney's playbook."

"To suggest that these ladies - each and every one of them - got together and orchestrated a campaign against Mr. Cosby is hard to fathom," he said. "This was not some big, deep sleeper cell that lay dormant for decades."

Several of his clients previously agreed to testify on behalf of the woman at the heart of the Montgomery County investigation and could be featured as corroborating witnesses should prosecutors file a criminal case.

In 2005, Andrea Constand, a former operations manager for Temple's women's basketball team, accused Cosby of drugging and assaulting her during a dinner at his Cheltenham mansion.

Prosecutors declined to pursue the case. Constand later filed a civil suit and lined up 13 other accusers - including Green, Serignese, and Bowman - as potential witnesses before she settled with Cosby out of court.

Montgomery County investigators reopened their criminal probe this year after Cosby's deposition in the suit became public, sources close to the probe have said. They have until January to decide whether to file charges under Pennsylvania's 12-year statute of limitations on felony sexual crimes.

District Attorney Risa Vetri Ferman and her first assistant, Kevin Steele, who will take over the office next month, have declined to discuss the investigation.

Constand's attorney, Dolores Troiani, has said her client agreed in August to cooperate with the revived criminal probe. Reached last week, Troiani said she could not comment on the status of the case.

Gloria Allred, a California lawyer who represents several other women accusing Cosby of sexual misconduct, said she had been in touch with Montgomery County investigators. None of Allred's clients is a target of the countersuit Cosby filed Monday.

"I will say this: The investigators are aware that I have many clients that are willing to testify in that criminal case if one comes forward," she said.

In their countersuit, Cosby's attorneys said that he "prides himself in the legacy and reputation he has earned throughout his life" and that the accusations have damaged his career.

They allege the seven timed their decision to go public just as news broke of Cosby's scheduled return to television in a new series for NBC. The network dropped plans for the show after the allegations became public.

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