Detention warrant was issued for Kemal Özkiraz, the coordinatior of the Eurasia Public Opinion Research Centre (AKAM), media reported on Tuesday.

Police raided Özkiraz’s home and workplace, to no avail. A lawyer representing him said Özkiraz would stop by the prosecutor’s office to give his statement on Wednesday.

The warrant was issued over his social media posts  what media said critical of Turkey’s military offensive in Afrin.

Özkiraz was among people who said the 2017 referenfum which gave more powers to the Turkish president Recep Tayyip Erdogan, had been rigged through unstamped ballot papers to ensure a “Yes” vote.

On Jan 22, Turkish troops entered Afrin area, which is controlled by the outlawed Kurdistan Workers’ Party’s (PKK) extension PYD. While most political parties in Turkey welcomed the offensive, police have detained, among others, many journalists for criticizing the operation since then.