The allegation is contained in a complaint of sexual harassment and voting corruption within the Recording Academy lodged by Dugan, who was placed on administrative leave last week amid allegations of workplace bullying.
According to Variety, Dugan, who replaced Portnow in the job last August, says she was removed from the CEO position after raising concerns over misconduct at the Academy, the awards body behind the Grammys.
The claim, filed with the Equal Employment Opportunity Commission (EEOC) in the US, accuses the Recording Academy of creating false pretext to place her on leave.
Dugan’s damning claim includes an allegation that Portnow raped a female recording artist, “which was, upon information and belief, the real reason his contract was not renewed.”
Portnow has unequivocally denied the allegation in a statement reported by Variety, which reads: “This document is filled with inaccurate, false and outrageous and terribly hurtful claims against me.”
Dugan’s EEOC report, which arrives just five days before the Grammys ceremony on Sunday January 26, also alleges that she was sexually harassed by the Academy’s general counsel, Joel Katz.
She says Katz attempted to kiss her at an expensive dinner, and that he repeatedly called her “baby”.
Katz has issued a statement through his attorney “categorically” denying the allegations.
She also alleges that the Academy’s board manipulates the voting process for the Grammys, stating that some board members are on “secret committees” which choose nominees or have relationships with nominated artists.
The complaint claims that the Board manipulates the nominations process, ensuring certain songs or albums are nominated when Grammys producer Ken Ehrlich wants a particular song performed during the show.
It also claims that the Board is permitted to add in artists for nominations who did not make the initial 20-artist list.
Dugan also claims she was also asked to offer Portnow a US$750,000 consulting contract.
The Academy has been asked for comment.
Dugan was dismissed last Thursday, just ten days before her first Grammy Awards, after the Academy accused her of misconduct against an unnamed employee.
The Recording Academy wrote in a statement to Billboard: “In light of concerns raised to the Recording Academy Board of Trustees, including a formal allegation of misconduct by a senior female member of the Recording Academy team, the Board has placed Recording Academy president and CEO Deborah Dugan on administrative leave, effective immediately.
“The Board has also retained two independent third-party investigators to conduct independent investigations of the allegations.”
Dugan replaced Portnow as Recording Academy CEO after the latter’s controversial final months in the position.
Portnow was heavily criticised for saying female artists needed to “step up” to gain recognition at the Grammy Awards, and a Variety report later alleged Portnow siphoned funds from a Recording Academy charity to cover the costs of the 2018 Grammy ceremony.
Ariana Grande, Lizzo and Lana Del Rey are among the leading nominees at Sunday’s Grammys ceremony.