Marzieh Hashemi, an American-born journalist working for an Iranian news outlet, has been released from U.S. custody after testifying before a grand jury in Washington, her representative said Wednesday. She is now with family at a Washington-area hotel, a friend told CBS News.

Hashemi, a 59-year-old anchor for Iran's Press TV, was arrested by FBI agents at Lambert International Airport in St. Louis last week. She was then transported to Washington and jailed for 10 days.

A court order unsealed Friday confirmed Hashemi was being held as a material witness in a criminal case. She was not charged with a crime.

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Marzieh entered D.C. District Court in street clothes and wearing a hijab just after 8 a.m. Wednesday, accompanied by her son Reza. The two left just after 5 p.m. Her two other children — Hossein and Sarah — were also subpoenaed. It's unclear if they completed their testimony.

Born Melanie Franklin in New Orleans, Hashemi is a veteran television presenter and producer for Press TV. The network, which is overseen by the government, called her detainment a "violation of free speech."

In a written statement, a family spokesperson also took issue with Hashemi's detainment.

"Marzieh and her family will not allow this to be swept under the carpet. They still have serious grievances and want answers as to how this was allowed to happen," the statement read.

More than two dozen supporters gathered this morning in front of the courthouse, claiming Hashemi's detainment was an act of oppression.

"If they thought they could take Marzieh and intimidate her into silence about speaking out against oppression in this country, they picked the wrong person," said Safiyyah Abdullah, a close friend.

Abdullah also announced protest marches and rallies will take place Friday in some 30 cities spread across nine countries.

Clare Hymes and Matthew Sheridan contributed to this report.