(KRON) -- A convicted sex offender who works at a San Jose boxing gym was arrested Thursday and charged with committing sex crimes against female gym members and an employee. Tristan Arfi, 41, of San Jose, is a manager at the boxing gym YBX Fitness on First Street downtown, prosecutors said. He is accused of committing multiple felony crimes against two gym members and a gym employee. Arfi has a prior 2019 conviction for committing lewd acts against a minor at a boxing gym in Menlo Park, the Santa Clara County District Attorney's Office said. During the San Jose Police Department's investigation, two victims separately told police that Arfi offered "free private massages." Prosecutors wrote, "Once each victim was alone with Arfi, both victims reported that he began to grope and caress them in a sexually inappropriate manner." Arfi is also accused of attempted extortion against an employee at the gym. The victim reported that Arfi refused to pay her for her work at the gym, unless she sent him nude photographs of herself, prosecutors said. Tristan Arfi's Nov. 21, 2024 mugshot was released by the Santa Clara County District Attorney's Office. Employees at the gym reported that Arfi forced them to sign a non-disclosure agreement when they worked at the gym, and that he would frequently threaten legal action if they discussed things they witnessed at the gym. "Non-disclosure agreements are invalid in California if they prevent a witness from disclosing information about unlawful acts in the workplace, such as harassment, discrimination, or – of course – a crime," the DA's office wrote. The gym manager will be arraigned at the Hall of Justice on December 23 for seven counts of sexual assault. Missing teen found with suspected pimp in Oakland The DA’s Bureau of Investigation believes there may be more victims. Anyone with information related to Arfi should contact Investigator Christina Hanks at [email protected] or 408-792-2851. District Attorney Jeff Rosen said Friday, "Our job as prosecutors will be to make sure he does not hurt anyone else ever again." The case was investigated by the San Jose Police Department and Santa Clara County District Attorney's Office Bureau of Investigation.