"I am not a liar. I am a truth teller," Barbara Bowman, one of four women added to a defamation lawsuit against entertainer Bill Cosby, said at a news conference Friday
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Four more women have joined Tamara Green’s federal lawsuit against entertainer Bill Cosby, claiming that public comments made about them by Cosby’s representatives after they came forward were defamatory, Joseph Cammarata, their attorney, said at a news conference Friday.

“Each of these women came out and publicly recounted the sexual assault and sexual abuse that they suffered at the hands of Mr. Cosby,” Cammarata said, “and in response Mr. Cosby branded each of these women liars.”

Green, 67, filed her suit against Cosby last December. In January Linda Joy Traitz and Therese Serignese joined the suit.

On Oct. 9, U.S. District Judge Mark Mastroianni refused to throw out Green’s lawsuit. Now Barbara Bowman, Joan Tarshis, Louisa Moritz and Angela Leslie are adding their names to the list of women who say Cosby, 78, defamed them.

Tarshis, 67, a former publicist, says Cosby drugged and sexually assaulted her in his bungalow on the set of The Bill Cosby Show in 1979. She went public last November and says afterward she was publicly called a liar by Cosby’s representatives as well as perfect strangers.

“Last spring I was with my father at his lawyer’s office and I had to go out to the car to get something,” she said Friday. “A car drove toward me and past me and as they passed me a woman spat out the window at me and yelled, ‘Liar! You’re a liar!’ I was incredibly shaken.”

Yet she says she does not regret coming forward.

“I’m glad I now have the opportunity to clear my name,” she says. “I am not a liar.”

Ex-model Bowman, 48, says Cosby sexually assaulted her three times in the 1980s. She was Jane Doe Number 7 in former Temple University employee Andrea Constand’s 2005 civil lawsuit against Cosby – which Constand settled in 2006. Constand, now 42, alleged Cosby drugged and sexually assaulted her at his Elkins Park, Pennsylvania mansion in January 2004. She is currently trying to get the confidentiality portion of it lifted. Last summer local authorities reopened the criminal investigation of her claims.

“I am not a liar. I am a truth teller,” Bowman said at the news conference Friday. “What happened to me was horrific, tragic and true.”

Moritz and Leslie were not at the press conference. Moritz, 69, an actress who was in One Flew Over the Cuckoo’s Next, says Cosby forced her to perform oral sex on him backstage at the Tonight Show more than 25 years ago.

Ex-model Leslie, 53, alleges Cosby forced her to masturbate him in his Las Vegas hotel room in the early 90s.

More than 50 women have now accused the entertainer of drugging and/or sexually assaulting them. Monique Pressley, his attorney and chief spokeswoman, declined to comment for this story. She has vehemently denied all the allegations against Cosby, as have all of his attorneys and spokespeople.

Another woman, Kristina Ruehli, 72, who was Jane Doe Number 12 in Constand’s lawsuit, also filed a defamation suit against the entertainer on Monday.

“Ms. Ruehli was the victim of an attempted rape by Mr. Cosby in 1965, when she was just 22 years old,” her attorney, Megan C. Deluhery, said in a statement to PEOPLE.

“She went public with her own story on November 21, 2014,” the statement continued. In response, the statement says, Cosby called the allegations “‘fantastical’ and ‘past the point of absurdity’ in an attempt to discredit Ms. Ruehli and the other victims who had come forward and to brand them as liars.”