Turkey's civil society swung from hope to despair on Tuesday after counter-terror police detained leading rights defender Osman Kavala just hours after a court ordered his release from jail.
Mr Kavala and eight other defendants were acquitted by a court outside Istanbul in the highly controversial Gezi Park trial.
But within hours, a new warrant from the Istanbul prosecutor's office called for his arrest as part of an investigation into a failed 2016 coup against President Recep Tayyip Erdogan's government, and under the charge of attempting to overthrow the constitutional order.
After his release from the heavily-guarded prison complex in Silivri outside Istanbul, where he has spent more than 800 days in pretrial detention, the official Anadolu news agency said Mr Kavala was taken by police to an Istanbul hospital for health checks before being formally detained.
The judge had earlier said there was "not enough concrete evidence" that he and the other defendants sought to overthrow the government.
Seven other defendants, who remain on the run, were not formally acquitted.
Mr Kavala, the only accused kept in jail throughout the trial, faced a life sentence without parole if convicted for his alleged role in orchestrating the Gezi Park protests of 2013 that presented the first major challenge to Mr Erdogan, then prime minister.
News of a fresh arrest came as supporters waited for him to be released from the Silivri court and prison complex, and was met with shocked silence, while his wife Ayse Bugra was visibly upset.
Mr Kavala has became a symbol of what critics say is a crackdown on civil society under Mr Erdogan, and received loud cheers as he left the packed courtroom in Silivri.
The mass protests of 2013 began over plans to demolish Gezi Park — one of the only green spaces in Istanbul's centre — but quickly spiralled into broader demonstrations against the government.
Critics have called the Gezi trial "a mockery" in which the prosecution failed to present any evidence of wrongdoing by the defendants.
And the re-arrest of Mr Kavala on new charges sparked condemnation from rights advocates.
"This is a vindictive and lawless move, further demonstrating that Turkey's justice system is under tight political control," Emma Sinclair-Webb, of Human Rights Watch, told AFP.
Amnesty International slammed the "cynical and outrageous detention" and called for his immediate release.
"This decision smacks of deliberate and calculated cruelty," Amnesty's Turkey campaigner Milena Buyum said in a statement.
"It is time for Turkey to end the relentless crackdown on dissenting voices."
