Natali Avazyan, a Turkish-Armenian human rights activist, tweeted on Tuesday that she was being taken into police custody, adding that the police had raided her brother’s apartment a few hours earlier.
The brief detention, for which no reason has yet been announced, came after Avazyan raised awareness for a boy with cancer whose father is in jail over alleged links to the Gülen movement.
She was released at midnight, according to another tweet.
Eight-year-old Ahmet Burhan Ataç was sent to Germany for treatment with the help of funds raised by Avazyan; however, his mother was unable to travel with him due to a passport restriction imposed by the Turkish government.
Missing his mother, Ahmet Burhan returned to Turkey a few days ago to be with her until the second phase of his treatment starts.
Turkey accuses the Gülen movement of orchestrating a 2016 coup attempt, although it strongly denies any involvement.
On the pretext of an anti-coup fight, more than 130,000 people were removed from state jobs while in excess of 30,000 others are still in jail and some 600,000 people have been investigated on allegations of terrorism.