The president of the Massachusetts Institute of Technology is admitting that not only did the school hide donations from Jeffrey Epstein—he wrote the accused sex trafficker a thank-you letter.

“It is now clear that senior members of the administration were aware of gifts the Media Lab received between 2013 and 2017 from Jeffrey Epstein’s foundations,” MIT President L. Rafael Reif said in a statement Thursday afternoon.

“Because the members of my team involved believed it was important that Epstein not use gifts to MIT for publicity or to enhance his own reputation, they asked [MIT Media Lab Director Joi Ito] to agree to make clear to Epstein that he could not put his name on them publicly.”

Reif said he also was present at a meeting of his senior team where attendees discussed Epstein’s crimes and donations.

The disclosure is the latest to rock the elite research institution, which has been roiled by a slow drip of revelations about close ties between the MIT Media Lab and Epstein, a registered sex-offender.

Reif’s Thursday statement summarized the preliminary findings of an investigation by outside law firm Goodwin Procter into Epstein’s connections to the Media Lab—an institute that exercised broad influence over the technology industry—and to Ito and the university writ large.

Reif noted that the law firm’s probe revealed that he had signed an acknowledgment letter thanking Epstein—listed as a “disqualified donor” in MIT’s own records—for a donation after he had pleaded guilty to a prostitution charge stemming from a sex-trafficking investigation.

“ I apparently signed this letter on August 16, 2012, about six weeks into my presidency,” Reif wrote. “Although I do not recall it, it does bear my signature.”

Reif wrote that Ito asked members of MIT’s senior team for permission to keep an Epstein donation in 2013, and they allowed it.

“They knew in general terms about Epstein’s history–that he had been convicted and had served a sentence and that Joi believed that he had stopped his criminal behavior. They accepted Joi’s assessment of the situation. Of course they did not know what we all know about Epstein now,” Reif said.

In July, federal prosecutors in New York charged Epstein with sex trafficking and accused him of paying dozens, if not hundreds, of underage girls for sexual acts. A money manager with a deep Rolodex of famous people, Epstein killed himself in jail while awaiting trial.

Ito resigned as head of the Media Lab after the New Yorker reported he had hidden the extent of Epstein’s involvement with the institute. Ito had also taken Epstein’s money for his own personal investments.

Reif concluded the letter by saying that “flaws in our processes” needed to be addressed. Goodwin Procter’s investigation is ongoing.

Epstein served as a liaison for the lab, courting prominent donors like Bill Gates, who gave $2 million to the lab after Epstein made overtures to him, according to emails published by the New Yorker. A spokesperson for Gates denied that Epstein ever directed Gates’ giving, and Ito hid Epstein’s involvement as an ambassador from his MIT superiors.

MIT did not immediately respond to request for comment, nor did Goodwin Procter.