Lawyer Firat Eposdemir, a member of the Istanbul Bar Association's board of directors, was arrested on January 25 on charges of "membership of an armed terrorist group" and "spreading terrorist propaganda" by an Istanbul court, local media reported.
Epozdemir was detained at Istanbul airport on 23 January as part of the investigation.
Istanbul prosecutors accuse Epozdemir of joining the terrorist group's WhatsApp group in 2015 at the height of clashes between Kurdish militants and Turkish security forces in the Kurdish-majority southeast of the country.
Ankara and its Western allies have branded the PKK a terrorist organisation for its bloody war, which began in 1984 and has since left more than 40,000 dead.
The government has been criticised for reducing the Kurdish issue to little more than a "terrorist" problem, ignoring the demands of the community, which makes up 15-20% of Turkey's 85 million population. | BGNES