Sadak was among approximately 80 people detained in simultaneous operations in three southeastern cities, police said. The operations were ordered by the Diyarbakır Chief Public Prosecutors' Office to take place in Batman, Mardin and Siirt. Many of the detainees are reportedly local officials from the pro-Kurdish Peace and Democracy Party (BDP).
The detainees were taken to local police departments for questioning. The BDP noted in a statement on Saturday that the police operations were ongoing.
The KCK investigation started in December 2009 and a large number of suspects, including several mayors from the BDP, have been detained in the case. The suspects are accused of various crimes, including membership in a terrorist organization, aiding and abetting a terrorist organization and attempting to destroy the country's unity and integrity.
The BDP says the raids are politically motivated and designed to stifle the Kurdish movement, but the prosecution and terrorism experts maintain that the KCK is a criminal organization whose purpose is to create an alternative state mechanism.
The latest raids coincide with efforts in Ankara to lift the parliamentary immunity of 10 lawmakers, nine of them from the BDP. This would pave the way to prosecute the deputies, a move that would weaken Kurdish representation in Parliament and could fuel tension in the Southeast.
Prime Minister Recep Tayyip Erdoğan last week said he favored stripping the pro-Kurdish deputies of their immunity after they were filmed in August chatting with and embracing armed PKK terrorists who had stopped their convoy on a road in the Southeast.
BDP deputies are often under investigation, accused of links to the PKK, but are protected from prosecution while they are in office. The BDP denies any outright ties to the PKK.
Erdoğan has pledged greater Kurdish political and cultural freedoms since his party came to power in 2002, while applying increasing pressure on the PKK and, occasionally, the BDP, which he calls the PKK's “political extension.”