A Google engineering director and a software developer have reportedly resigned from the company over the dismissal of AI research Timnit Gebru, who was fired from the company after refusing to retract an academic paper critical of the company’s AI technology. The director, who worked for Google for 16 years, said: “We cannot say we believe in diversity, and then ignore the conspicuous absence of many voices from within our walls.”

Reuters reports that an engineering director and a software developer at Google have quit over the recent dismissal of AI ethics researcher Timnit Gebru. David Baker, an engineering director focused on user safety, left the company after 16 years because Gebru’s exit “extinguished my desire to continue as a Googler,” he said in a letter. Baker added: “We cannot say we believe in diversity, and then ignore the conspicuous absence of many voices from within our walls.”

Google software engineer Vinesh Kannan stated on Wednesday that he left the company because Google mistreated Gebru and April Christina Curley, a recruiter who claims she was wrongly fired last year.

Breitbart News reported last December that Gebru alleges that she was approached by a manager at Google and asked to retract or remove her name from a research paper that she had coauthored as an internal review at Google found the contents of the paper objectionable.

The paper discussed ethical issues raised by advances in artificial intelligence working with language, an area of research that Google believes is important to the future of its business. Gebru objected to retracting the paper or removing her name from it, calling the practice unscholarly. A short time later she was fired by the Silicon Valley giant. A Google spokesperson alleged that she resigned and was not fired but declined to comment further.

Speaking to NPR, Gebru stated: “My theory is that they had wanted me out for a while because I spoke up a lot about issues related to black people, women, and marginalization. They wanted to have my presence, but not me exactly. They wanted to have the idea of me being at Google, but not the reality of me being at Google.”

Google declined to comment when asked by Reuters but pointed to previous statements that say that the company is working to restore employees’ trust following Gebru’s departure and that it disputes Curley’s unfair dismissal accusation.