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Other Women Accusing Bill Cosby of Sexual Assault Could be Called to Testify: Expert

Potentially any of the more than 40 accusers who claim Cosby made unwanted sexual advances toward them could be permitted to testify, experts say.

The woman accusing Bill Cosby of drugging and sexual assaulting her in 2004 may not have to take the stand alone if the criminal case against the comedian moves to trial.

Potentially any of the more than 40 accusers who claim Cosby made unwanted sexual advances toward them could be permitted to testify to establish a "signature," a prominent Pennsylvania legal expert told NBC News.

Prosecutors in Montgomery County, Pennsylvania, on Wednesday filed the first-ever criminal charge against Cosby — for aggravated indecent assault — just before the statute of limitations ran out in the case from 12 years ago.

The probable cause affidavit claims that the once-revered and powerful entertainer gave the victim pills, then assaulted her at his suburban Philadelphia home.

Cosby is charged with three counts of aggravated indecent assault, a second-degree felony, and was freed Wednesday on $1 million bail. He was also ordered to surrender his passport.

Read the affidavit of probable cause here

Andrea Constand, a 42-year-old former Temple University basketball coach, is the victim named in the affidavit. She filed a civil lawsuit against Cosby in 2005 with allegations that mirror those in the criminal case. That suit was settled in 2006.

Her attorney released a statement Wednesday praising Montgomery County police and prosecutors.

Constand's claim is one of dozens against Cosby, 78. Most of the alleged incidents are decades old. Cosby has denied all claims and has filed defamation lawsuits against seven of his accusers.

Related: The Cosby Accusers Speak Out on Dateline

"The law generally prevents the prosecution from admitting a defendant's prior bad acts because we are afraid that juries will convict defendants because of something other than the crime for which he is being tried. But there are exceptions," said Wesley Oliver, who is the criminal justice program director at Duquesne University and has served as a NBC News legal analyst.

But when defendants have a "modus operandi" — when their crimes almost bear the defendant's signature because they are committed in such a similar way — rules of evidence dictate that testimony from other very similar crimes can be admitted.

Related: Bill Cosby Sues Seven Sexual Assault Accusers for Defamation

"In all, or almost all, of the cases involving Bill Cosby, the alleged victims describe Cosby giving her a pill that renders her unconscious and awakens to find that she's been assaulted," Oliver said. "And there are a lot of women who describe this occurrence."

"This is as close to a signature sexual-assault crime as it gets," he added.

This means that while Cosby is charged with one count of aggravated indecent assault pertaining to one alleged victim, other accusers who can speak about the same alleged behavior can appear in court.

Court procedures indicate that it is up to the district attorney and those trying the case to call on these alleged victims, and then it would be up to the judge in the case to allow them to testify.