Story highlights Special Counsel Robert Mueller is investigating Russia and possible ties to Trump's campaign

Former Trump campaign chairman spokesman Jason Maloni was subpoenaed

(CNN) Jason Maloni, former Trump campaign chairman Paul Manafort's spokesman, testified Friday at the US District Court in DC to before a grand jury as part of special counsel Robert Mueller's investigation.

Arriving at the courthouse, Maloni was asked if he was ready to testify.

"Hell yeah," he responded, giving a thumbs up.

Maloni testified as Manafort is under federal investigation as part of Mueller's Russia investigation. The probe into Manafort is largely focused on his past work for the former ruling party in Ukraine, which was ousted amid street protests over its pro-Russian policies.

Following his testimony, Maloni spoke briefly to reporters.

Read More