Wife of detained Egyptian business tycoon interrogated
Bahira El-Shawi was released pending further investigation into the charges against her, according to lawyer Nasser Amin.
It came a few days after she posted a video on YouTube calling for the release of her detained husband and son, Seif.
It was not immediately clear what she was charged with.
Thabet, the Juhayna Industries major shareholder and CEO, was detained in December on terrorism-related charges. His son, who took over the company, was arrested two months later over similar accusations.
The two men were accused of allegedly being involved in financing a terrorist group - commonly a reference to the Muslim Brotherhood.
The ministry accused Yehia Mahran Othman, a senior Brotherhood member, of playing a key role in the alleged conspiracy.
The Muslim Brotherhood has officially been designated a terrorist group in Egypt since 2014.
The Muslim Brotherhood's Mohamed Morsi, Egypt's first-democratically elected president, was overthrown in a coup in 2013.
Such charges have been widely deployed in a crackdown that has swept up dissidents from across the political spectrum. They and are now being used to target business people, Amnesty said.
Local and international human rights organisations reported that there are about 60,000 political detainees and prisoners behind bars in Egypt, an accusation frequently denied by the Egyptian government, led by President Abdel Fattah Al-Sisi.