Samsun police detained a man for wearing a Batman-themed hero T-shirt, Turkish journalist Can Ertuna tweeted on Sunday.

He also claimed that the man was questioned by anti-terror police for three hours.

The hero T-shirts have become a contentious issue when Gökhan Güçlü, one of the suspects on trial for an assassination attempt against President Recep Tayyip Erdoğan on the night of the coup, was thrown out of the courtroom last Thursday for wearing a T-shirt bearing the word “hero” because it caused tension between the parties during the hearing.

Since then, Turkish police have rounded up 13 people including four university students, two factor workers and a waiter for wearing T-shirts bearing the word “hero” in Eskişehir, Aydın, Elazığ, Antalya, Sakarya, Canakkale and Erzurum provinces.

President Recep Tayyip Erdogan said people detained over coup charges should wear a single outfit, like in Guantanamo.

In the meantime, the textile firm that manufactures the hero T-shirts stopped production and the T-shirts were withdrawn from sale in stores and online.