An Istanbul prosecutor has launched an investigation into the popular Turkish TV series, Çocuklar Duymasın over a book linked with the Gülen movement that was spotted as a in the background during last week’s episode.

Barış Köprüleri: Dünyaya Açılan Türk Okulları [Bridges of Peace: Turkish Schools Opening to the World] appeared on the shelf as a background decor during the sitcom’s last episode on July 30.

Meanwhile, the hosting TV channel Kanal D was fined TL 562,000 [$160,000] by the the Radio and Television Supreme Council (RTÜK) for

Çocuklar Duymasın, which translates into English as Don’t Let the Kids Hear, started as the story of a married couple on the edge of divorcement and their relationship with other family members as well as neighbors, in 2012. Appeared on several TV channels on different time periods, the family series continues its seventh season on the private Kanal D TV channel.

Amid uproar on social media over the past week, the Istanbul Public Prosecutor’s Office launched an investigation into the drama on charges of making propaganda on behalf of the Gülen movement, which the government accuses of masterminding the July 15, 2016 coup attempt.

The producer Birol Güven earlier apologized for the scene on social media.

The movement denies involvement.

The book in question is a compilation of some 25 articles written by politicians, journalists and scholars about the schools established by Gülen movement supporters across the world.

Turkey earlier arrested some 55,000 people, among them a comedian and a TV director, over links to the movement since last summer. Police, on many occasions, seized books written by Fethullah Gülen, the cleric that inspires the movement, and as well as by his sympathizers as terror evidence.