Grand jury questions social media advisor to key Trump ally Roger Stone
Jason Sullivan (C), a social media expert who worked for longtime Trump adviser Roger Stone, arrives at U.S. District Court to respond to a subpoena and testify before Special Counsel Robert Mueller's grand jury in Washington, U.S., June 1, 2018. REUTERS/Kevin Lamarque

A social media expert who worked with influential Donald Trump ally Roger Stone during the 2016 U.S. presidential race testified before a federal grand jury on Friday after being subpoenaed by the special counsel investigating potential collusion between Trump’s campaign and Russia.

Jason Sullivan arrived at the federal courthouse in Washington at around 9 a.m. and left the courthouse at around 11:30 a.m. After his closed-door grand jury testimony ended, Sullivan declined to comment on what questions Special Counsel Robert Mueller’s team had asked him.

Knut Johnson, one of two lawyers who accompanied Sullivan to the courthouse, said that because the testimony was part of an “ongoing investigation,” neither Sullivan nor his lawyers wished to discuss details of it. Johnson said Sullivan had been “open” and “truthful” in his statements to the grand jury.

Sullivan is a social media and Twitter specialist who worked for an independent political action committee set up by Stone, a long-time Trump adviser and backer, to support Trump’s campaign.

Stone has said Sullivan is one of eight of his associates approached by investigators working for Mueller, who was appointed by the Justice Department in May 2017.

Mueller is probing Russian involvement in the 2016 election. This outreach to Stone’s associates suggests Mueller may be focusing in part on Stone and whether he might have had advance knowledge of material detrimental to Trump’s 2016 Democratic opponent Hillary Clinton that U.S. intelligence agencies have concluded was hacked by Russia and sent to WikiLeaks founder Julian Assange, who published it.

Stone did not immediately respond to a request for comment on Sullivan’s grand jury appearance.

The Republican president has denied collusion and called Mueller’s investigation a “witch hunt.”

Reporting by Mark Hosenball; Editing by Will Dunham