Kate Upton refuses to participate in Guess‘ investigation into sexual misconduct allegations against its co-founder, Paul Marciano.

“I just learned that Guess hired Paul Marciano’s PERSONAL lawyer to run their internal ‘investigation,'” Upton, 25, fumed on Twitter on Wednesday. “I’m truly disheartened to learn that Guess is treating this abuse of power and sexual misconduct (to multiple women) in such a manner.”

She continued, “I shared my story to help create long-term change at the highest levels of the industry and corporate ladder. I also wanted to empower others to share their stories to stand up for change — whether as a victim of or as a witness to this behavior.”

“Hearing how this ‘investigation’ is being conducted, and also knowing a strong fear of retaliation still exists within Guess’ corporate offices, is extremely disappointing and upsetting,” the Sports Illustrated stunner added. “The #MeToo movement is not one of smoke and mirrors, or for corporate office PR stunts to impress shareholders — it’s a call to action for TRUE change.”

“To conduct an investigation like this seems like a stunt, and is a clear indication to me that Guess is not taking these claims seriously, nor are they committed to making changes at the highest levels. Until Guess makes a commitment to conduct an unbiased investigation, I have declined to participate,” she wrote. “I look forward to participating if and when Guess retains a truly independent firm to run the entire investigation.”

Guess announced earlier this month it would launch an investigation into various claims of sexual misconduct against Marciano, who stepped away from his work with the brand in light of the myriad allegations against him.

“The Company is committed to completing an extensive and impartial investigation into all of the facts. On February 7, 2018, the Board of Directors formed a Special Committee comprised of two independent directors to oversee an ongoing investigation into recent allegations of improper conduct by Paul Marciano,” Guess said at the time. “Mr. Marciano adamantly denies the allegations.”

Upton spearheaded the campaign to oust Marciano, alleging that he groped and sexually harassed her repeatedly during her tenure with the brand in 2010, and she isn’t alone in accusing the fashion mogul of abusing his power in the industry.

Playboy model Kristina Shannon accused Marciano of promising her a modeling career in exchange for sexual favors.

Model Miranda Vee accused Marciano of sexually harassing her and “passing” her to his close friend, Mohamed Hadid (father of supermodels Bella and Gigi Hadid, the latter of whom is a former Guess Girl). Vee alleged that Mohamed date raped her during a meeting to set up a test shoot for Guess, and she later filed a police report regarding the alleged incidents.

Hadid and Marciano have both vehemently denied all allegations of sexual misconduct against them.

A rep for Guess did not immediately return a request for comment.