Joi Ito looks off-camera with a solemn expressionRoger Barnett / Flickr

On Saturday, Joi Ito resigned from his position as director of the MIT Media Lab, according to an email sent to The New York Times.

“After giving the matter a great deal of thought over the past several days and weeks,” Ito wrote in the email, “I think that it is best that I resign as director of the media lab and as a professor and employee of the Institute, effective immediately.”

The resignation comes after mounting concern over Ito’s ties with Jeffrey Epstein, a serial rapist and billionaire who had been a significant donor to the lab and to MIT. Epstein donated as much as $800,000 to MIT-related projects over the years, including Ito’s own venture fund.

On August 15th, Ito publicly apologized for his cultivation of Epstein as a donor, which took place after Epstein’s 2008 conviction for soliciting an underage prostitute. His position as director became controversial in the wake of that apology, with some lab employees resigning in shock, while others offered a public show of support.

However, a New Yorker exposé published Friday revealed that Ito had gone to significant lengths to conceal Epstein’s donations, typically marking them as anonymous in internal records. According to The New Yorker, the secrecy was so extensive that Ito began to refer to Epstein as Voldemort, or “he who must not be named.”

The New Yorker piece also suggests Epstein may have served as an intermediary between the MIT Media Lab and other philanthropists, including Bill Gates. The piece cites emails showing that $2 million in donations from Gates were described as “directed by” Epstein. Epstein’s name is concealed in the official records, which say only, “Gates is making this gift at the recommendation of a friend of his, who wishes to remain anonymous.”

Speaking to the Times, Gates’s representatives pushed back against that description, saying, “any account of a business partnership or personal relationship between [Epstein and Gates] is simply not true.”