Following Kate Upton’s accusations of sexual and emotional harassment against Guess co-founder Pail Marciano, the brand launched an internal investigation into the numerous claims of sexual misconduct against Marciano. Upton claims that Marciano groped her breasts and forcibly touched the rest of her body when she was 18 years old. She also accused him of being emotionally abusive, even calling her a “fat pig” once. Besides Upton, two other models who have worked with Guess shared similar stories.

Today, Upton took to Twitter to express her disgust with the way Guess is dealing with the investigation. According to her, Guess hired Marciano’s personal lawyer to run their internal investigation. She has pledged to not cooperate with the investigation until the fashion brand commits to an “unbiased investigation” and “retains a truly independent firm to run the entire investigation.”

“I’m truly disheartened to learn that Guess is treating this abuse of power and sexual misconduct (to multiple women) in such a manner,” Upton wrote. “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.”

Upton said that besides the suspicious way that the investigation is being conducted, there is also a “strong fear of retaliation” within “Guess corporate offices.”

“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,” she continued. “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.”

Marciano has denied all of Upton’s claims, but he stepped down in February from his role as Guess CEO. Guess share prices have fallen more than 20 percent since Upton made her initial claims against the brand co-founder.

Besides Upton, Playboy model Kristina Shannon has also stepped forward accusing Marciano of promising her a modeling career in exchange for sex. In addition, model Miranda Vee accused Marciano of sexually harassing her and “passing” her on to Mohamed Hadid (father of Bella and Gigi Hadid) in a since-deleted Instagram post. Vee went on to accuse Hadid of date raping her; she filed a police report after the incidents in question. Hadid responded by denying her claims and saying he would file a defamation suit against Vee.