Turkish authorities should release Halk TV’s editor-in-chief Suat Toktaş, who was arrested this week after airing an interview with an expert court witness, the Committee to Protect Journalists said Friday.

“Suat Toktaş’ arrest and the detaining of the other Halk TV personnel is a political move by Turkish authorities to silence critical voices,” said Özgür Öğret, CPJ’s Turkey representative. “The authorities should immediately release Toktaş, lift the measures of judicial control imposed on other Halk TV staff, and stop using the legal system to harass the media.”

Istanbul prosecutors opened an investigation against Halk TV following a Monday broadcast interview with an expert witness used in municipal investigations, alleging that the interview was secretly recorded without permission and attempted “to manipulate a trial by exposing the name of the court expert in a way that would make [him] a target.”

In a Monday press conference, Istanbul Mayor Ekrem İmamoğlu alleged that the expert witness, who has been involved in multiple investigations against the opposition-controlled municipality, frequently did not offer opinions in their favor. Istanbul prosecutors also opened an investigation against İmamoğlu following the press conference for “making a target” of the expert.

An Istanbul court arrested Toktaş pending trial on Wednesday, and released under judicial control Halk TV hosts Barış Pehlivan and Seda Selek, along with program coordinator Kürşad Oğuz and director Serhan Asker under judicial control, banning them from foreign travel.

Pehlivan and Selek were detained by the police in Ankara on Tuesday. Halk TV released a statement on Wednesday saying that Oğuz had recorded the conversation and Toktaş authorized it to be aired, which led to their detention in Istanbul.

CPJ’s email to Istanbul’s chief prosecutor did not receive a response.