The 3rd Panel Chamber of the Istanbul Regional Court of Justice Friday overturned the acquittal of nine of the 16 defendants implicated in the 2013 Gezi Park protest against the removal of trees in the park, ordering that the case be sent back to the court of first instance for a retrial.

The nine defendants were acquitted last February on charges related to the organization of protests in Gezi Park, Istanbul, including “attempting to overthrow the government of the Republic of Turkey or preventing the government from doing its duty.” Among these people is philanthropist Osman Kavala, who recently failed in his attempt to challenge his three-year-long detention in the Turkish Constitutional Court.

February’s acquittal came as a surprise to many, as the arrests and the subsequent trial of the Gezi protesters were seen by critics as an attempt by President Recep Tayyip Erdoğan to silence opposition. The judge at Istanbul’s 30th Heavy Penal Court had considered that there was “not enough concrete evidence” against the defendants to convict them.

The appeals court cited among its reasons for the decision the lower court’s failure to consider certain pieces of evidence, noting also that a second case against Kavala should be considered.

A date for the retrial has yet to be confirmed.