Chris Krebs
First director of the US agency CISA, fired by tweet after calling the 2020 election the most secure in American history.
Krebs led the Cybersecurity and Infrastructure Security Agency from its creation in November 2018. Ahead of the 2020 presidential election the agency ran Rumor Control, a site that rebutted claims of voter fraud one at a time. On 12 November CISA and the election officials it worked with declared the election the most secure in American history. Five days later Donald Trump announced on Twitter that Krebs had been fired.
He then set up the consultancy Krebs Stamos Group with Alex Stamos, which SentinelOne bought in 2023. No relation to the journalist Brian Krebs, something both have presumably explained more often than they'd like.