"I'm not certain he will have any choice but to dismiss the entire indictment against Harvey Weinstein", Brafman said.
He says that as of now, DiGaudio has "no active role" in the Weinstein investigation but remains on duty.
Weinstein was once a juggernaut in the entertainment industry until a pair of Pulitzer Prize-winning stories from the New York Times and the New Yorker published in October 2017, detailing accusations from several women.
An unnamed woman is argued to also have had email exchanges with Weinstein that show the encounters were consensual. Rather, "it only speaks volumes about the Manhattan D.A.'s office and its mishandling of my client's case".
The dismissed charge was one count of criminal sexual act in the first degree based on allegations made by actress Lucia Evans, who publicly accused Weinstein past year of forcing her to perform oral sex in 2004, the Daily Beast reported.
"Over 80 women have accused Harvey Weinstein of sexual violence and if our justice system fails to hold him criminally accountable then something is wrong with our justice system", the lawyer told reporters.
After the hearing, the Manhattan district attorney's office released a letter it had sent to Mr Brafman last month which said that a witness had told prosecutors that she had heard a version of the alleged assault from Ms Evans that was different from the account Ms Evans had originally given prosecutors.
Evans' attorney says the decision does not "invalidate the truth of her claims". Weinstein, 66, has pleaded not guilty and is free on $1 million bail.
Ms Evans's lawyer, Carrie Goldberg, said her client's account of events had been accurate. Others said prosecutors had discovered old personal writings by Evans in which she suggested her encounter with Weinstein was consensual.
He is due back in court on December 20.
Images of Weinstein in handcuffs were seen by many women as a cathartic moment in the MeToo reckoning.
Evans was one of three accusers in the case against Weinstein.
Prosecutors said in a letter unsealed Thursday that they learned weeks ago that a female friend who was with Evans the night she met Weinstein had given a police detective a contradictory account of what happened. Weinstein had promised to get her an acting job if she agreed to perform oral sex, and she agreed, it said.
An attorney for Weinstein has said that he plans to file motions to dismiss each of the remaining charges. The Associated Press does not identify alleged victims of sexual assaults unless they come forward publicly, as Evans has done.
He walked into the criminal court in downtown Manhattan dressed in a dark suit, tie and white shirt for the brief hearing that scored at least an initial win for his defence attorney Ben Brafman.
"Nothing in the disclosure relating to count six impacts the strength of the remaining case and the remaining counts in the indictment, all five of them, including predatory sexual assault", she said. Brafman has called the charges against Weinstein a product of political pressure amid the (hash) MeToo outcry.
He is now free on $ 1 million bail.