(CNN) David Sirota, a journalist and social media provocateur, was formally announced Tuesday as a new senior adviser and speechwriter for the Bernie Sanders campaign.

Sirota, who is known for both his reporting and combative Twitter presence, had been informally advising the campaign on a trial basis since the day after Sanders formally launched his 2020 bid for the presidency last month. But shortly before his hiring was announced, Sirota began erasing old tweets, many of which ran contrary to Sanders' call last month for supporters and surrogates to adopt a more friendly tone in their public exchanges with political rivals.

According to campaign manager Faiz Shakir, Sirota began the trial arrangement, in which he would assist Sanders with speechwriting, on Feb. 20, a day after Sanders made his candidacy official. Sirota left his post with the Capital and Main website on Feb. 14, Shakir said. He then signed a formal letter to become the campaign speechwriter on March 11. The trial period was to see how Sanders, who traditionally prefers to handwrite his own speeches on yellow-lined paper, would work with a speechwriter.

Sirota did not respond to CNN's request for comment on his new role with the Sanders campaign.

Sirota's last byline for Capital and Main was on Feb. 6, an interview with Washington Gov. Jay Inslee, who has since announced his own candidacy. In a statement posted on Twitter, Guardian editor John Mulholland, said Sirota was last published in the newspaper in December, and that Sirota's first contact with the Sanders campaign did not come until mid-January.

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