Hamza Yalcin was being held in a Spanish jail after Turkey requested an international arrest warrant.
Thousands of striking students have taken to the streets of Barcelona to defend the forthcoming Catala independence referendum, while firefighters also held a similar protest.
Spanish police have seized 300 kilos of marijuana and more than 30,000 examples of fake designer underwear following a raid in the Valencian autonomous community.
"None of us know where it is."
Ada Colau is against independence but says Mariano Rajoy's government has worsened the standoff with the Catalan regional government.
A Catalan flag marked with a "No" flies from the balcony of Luis Filgueras, stating his rejection of independence in a region where leaders are bent on holding a referendum on October 1st.
Catalan police warned on Wednesday that public disorder may erupt as Spain orders the authorities to seal polling stations and stop the region holding a referendum on independence.