A former aide to Donald Trump found himself at centre of a furore after insisting he would refuse to co-operate with an FBI inquiry into alleged links between the President’s campaign team and Russia.
Mr Nunberg, who worked on Mr Trump's presidential campaign, complained in a series of interviews with US media about being asked to share his email conversations with other former campaign aides.
How did Sam Nunberg make his name?
Mr Nunberg is a former political adviser who initially worked for the Mitt Romney presidential campaign in 2008. He was later hired by right-wing activist group the American Center for Law & Justice (ACLJ) to oppose the construction of a mosque near the World Trade Center site.
It was at the ACLJ where he met Trump adviser Roger Stone, whom Mr Nunberg described as his mentor.
The 36-year-old was later hired by the Trump campaign, but lost his job in February 2014 after arranging a Buzzfeed interview with Mr Trump, which ended up being highly critical of the future president.
Mr Nunberg was rehired a year later as a communications adviser.
How did he lose his job with the Trump campaign?
After helping Mr Trump prepare for his first televised Republican debate in August 2015, Mr Nunberg was fired again after Facebook posts featuring racially charged language resurfaced.
In March 2016, Mr Nunberg endorsed Ted Cruz for the Republican nomination, saying Mr Trump did “not have a coherent political ideology”. Later that year, former White House communications director Hope Hicks hit back, branding Mr Nunberg a “highly self-destructive individual”.
Mr Trump sued Mr Nunberg for $10 million (£7.2m) in July 2016, alleging he had breached confidentiality agreements by discussing the billionaire after he had left the presidential campaign team. The pair “amicably” settled the following month.
What exactly did Mr Nunberg say to US media this week?
“What they sent me was absolutely ridiculous,” Mr Nunberg said of Mr Mueller’s subpoena, during the now infamous appearance on MSNBC.
“They wanted every email I had with Roger Stone, and with Steve Bannon. Why should I hand them emails from November 1, 2015?”
Asked if he was concerned about potential contempt of court charges if he failed to hand over the emails, Mr Nunberg suggested he was not.
“Let him arrest me,” Mr Nunberg told the Washington Post. “Mr Mueller should understand I am not going in on Friday.”
He added: “I’m not spending 80 hours going over my emails with Roger Stone and Steve Bannon and producing them.”
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