Timnit Gebru, a co-leader of Google’s Ethical Artificial Intelligence team, said late Wednesday that she’d been abruptly fired from the search giant over an email she sent to colleagues. 

Gebru, a prominent AI researcher, has done studies on the dangers of facial recognition bias and has spoken out on the lack of diversity in the tech industry. In the wake of her departure, more than 1,400 Google workers, as well as more than 1,800 other industry professionals, signed an open letter in support of Gebru.

“Instead of being embraced by Google as an exceptionally talented and prolific contributor, Dr. Gebru has faced defensiveness, racism, gaslighting, research censorship, and now a retaliatory firing,” the letter read.

In a series of tweets Wednesday night, Gebru said she was terminated for a message