MIT administrators are erasing links to Walter Lewin, an extremely popular, now-retired physics professor, after an internal investigation determined he had been sexually harassing at least one female student online.

Although the 78-year-old retired from MIT in 2008 and taught his last online course in 2013, the university recently pulled his lectures off their online education website, MITx, as a precaution against him contacting any other students. The lectures, which would draw as many as 10,000 viewers a day, were also deleted from the education platform edX, the Washington Post reports.

According to a press release, the school began investigating Lewin when a female student filed a complaint in October. It's not clear when she took Lewin's online class, though she says that's when the harassment began and reportedly named other students who'd been subjected to inappropriate behavior. The university reportedly read correspondence between Lewin and several female students and concluded sexual harassment had occurred. His lectures were pulled not long after.

[image via YouTube]