A former Amazon director who joined in June 2022, a few months before Musk acquired Twitter in November, Irwin quickly earned the new Twitter owner’s trust and became one of his top executives at the company, overseeing content moderation, after the high-profile departure of the company’s former head of trust and safety, Yoel Roth.

While it’s not yet clear why Irwin has left Twitter, sources at Twitter have speculated about whether her departure might be connected to Musk’s recent criticism of the company’s decision to moderate content from conservative news site the Daily Wire.

Twitter’s approach to content moderation has become much looser, and controversial, under Musk, who has described himself as a “free-speech absolutist.” Earlier this week, an anti-hate group said it had flagged 100 tweets with racist, homophobic, and other abusive content posted by users of Twitter’s premium $8 per month Twitter Blue service, and that 99 of the tweets were sill available on Twitter four days later.

Irwin’s role as one of the top executives at Twitter has taken place during a tumultuous period at the company, as Musk has laid off thousands of employees and advertisers have fled. In a January Daily Beast profile, a former colleague of Irwin’s described her as someone who “thrives in environments that are on fire.”

After Musk eliminated Twitter’s public relations department, Irwin often served as the company’s de facto spokesperson, commenting about Twitter’s policies to reporters and regularly engaging with Twitter users about content moderation decisions.

In April, after a user criticized Irwin for allowing Nazi-related content on the platform, she tweeted back that “I would never defend Nazis and I don’t know anyone at Twitter that would. I had family members who were burned to death by Nazis. I do however believe in free speech, even speech I disagree with or despise. There are limits and we will restrict the reach of hateful content.”