I read Tristan's allegation from https://cims.nyu.edu/~tristanb/statement.pdf, and he didn't make it clear if threats to him were made over email, texts, calls or during personal meetings, so it is not clear if the whole thing was in writing.
He mentioned that they had meetings:
I asked to speak the following week. On Friday, September 4th, I was asked
whether I could meet that day; I again said the following week. At 12:45 on
Sunday, September 6th, I was asked whether I could meet “at any point today.”
Sebastien Bubeck joined. The three of us spoke twice that afternoon. Levent
was not on the calls.
He mentioned that they had meetings:
I asked to speak the following week. On Friday, September 4th, I was asked whether I could meet that day; I again said the following week. At 12:45 on Sunday, September 6th, I was asked whether I could meet “at any point today.” Sebastien Bubeck joined. The three of us spoke twice that afternoon. Levent was not on the calls.