An American newscaster for the Iranian government’s Press TV network, who was detained by the US government without being charged, has complained of mistreatment as she was held as a material witness in a criminal case.

“This is something that needs to be condemned across the table,” said Marzieh Hashemi, whose 10-day detention ended when she was released late on Wednesday. “It is not about me. It is about the US justice department and government – that they feel that they can just take people’s rights away, sweep them off of the streets, hold them in the name of being a material witness and not charging them … indefinitely.”

Hashemi’s detention and the limited details initially made available by authorities have prompted condemnation in the US and abroad, especially among press freedom and Muslim-advocacy groups including the Committee to Protect Journalists and the Council on American-Islamic Relations.

Those concerns were magnified when Hashemi’s family alleged that while in custody, Hashemi, an observant Muslim, was denied halal food and had her hijab forcibly removed.

Hashemi confirmed to the Guardian she was made to remove her hijab during booking for her mugshot and while walking in common areas of the detention facility.

“I said I want a scarf on,” Hashemi said. “I’m a Muslim woman, I have the right to wear hijab. And I said [it’s] freedom of religion. What you’re doing is illegal.”

She also said she barely ate for the first three days, save for an apple given to her by a corrections officer, while her request to be provided with halal food was processed.

If I haven’t committed a crime and I’m not being charged with a crime why would I feel [it] necessary to run? Marzieh Hashemi

Authorities have not released an explanation for Hashemi’s detention but it appears related to her primary residency being in Iran. US law allows the government to arrest and hold “material witnesses” if a judge agrees with prosecutors that the individual has information that is important to a criminal proceeding and may flee if simply subpoenaed to appear in court.

Hashemi denied strongly that she constituted a flight risk and said her attorney unsuccessfully motioned for the presiding judge to release her.

“If I haven’t committed a crime and I’m not being charged with a crime why would I feel [it] necessary to run?” Hashemi said.

Laura Pitter, senior national security counsel in Human Rights Watch’s (HRW) US program said that one of the problems with material witness laws is that the warrants are “issued in secret so we don’t know what they are based on”.

“Another problem is that the process for challenging the detention is often conducted in secret so we don’t know what the grounds are for even using them in the first place or whether the process has been fair,” added Pitter, who has studied the laws with HRW, particularly its expanded usage after 9/11.

The law’s usage in the federal system is currently uncommon. According to the Washington Post, Hashemi’s case is the first such filed in federal court in Washington this year, “and the court’s electronic docketing system indicates only two such cases were filed last year. Both are under seal.”

In other jurisdictions, usage is less rare. In Hashemi’s home city of New Orleans, the district attorney requested more than 150 material witness warrants over an eight-year period, many of which were filed against crime victims hesitant to testify.

Hashemi said she was not at liberty to discuss the exact nature of the case she was detained to testify on, but said she was questioned in front of a grand jury on four separate occasions, which was confirmed by disclosures made in a federal court order on Thursday.

Hashemi said the case “had a lot to do with me being an American and where I live, which is the Islamic Republic of Iran, and related to a job situation”.

Last week a US government source told Reuters that the grand jury was hearing arguments on Wednesday whether Hashemi’s employer, Press TV, is a “propaganda outlet” that failed to register with the justice department as a “foreign agent”.

Neither the FBI or the DoJ responded to a request for confirmation.