ISTANBUL (Reuters) - A Turkish sociologist who researched the treatment of minority Kurds and has become a cause celebre for human rights groups was acquitted for the fourth time on Friday of bombing Istanbul's Spice Bazaar in 1998.
Pinar Selek was arrested shortly after the explosion, which killed seven people and wounded more than 100, but freed 2-1/2 years later after experts said the blast had been caused by the accidental ignition of a gas cylinder.
Three formal acquittals followed between 2006 and 2011, but the Istanbul criminal court reopened the case again, and last year sentenced Selek, who lives in France, to life in prison.
The Supreme Court of Appeals overturned the conviction in June, and on Friday the latest retrial produced another acquittal.
Selek worked as a sociologist researching Kurdish issues in the mid-to-late 1990s and had contact with the separatist guerrillas of the Kurdistan Workers' Party (PKK), designated a terrorist group by Turkey, the European Union and the United States.
Turkish and foreign human rights groups say it was these contacts that made Selek a target for the judiciary, which they accuse of using broad anti-terrorism laws, under which dozens of journalists have been jailed, to silence dissent.
The U.S. group Human Rights Watch has described Selek's 14-year judicial ordeal as a "travesty of justice", saying there is substantial evidence that the explosion was due to a gas leak.
Last week, police raided media outlets close to the U.S.-based Muslim cleric Fethullah Gulen, whom Erdogan has accused of plotting to topple him, and arrested a number of people on suspicion of belonging to a terrorist group.
Erdogan denies using the judiciary for political persecution and defended the operation as a response to "dirty operations" by his enemies.
Reporting by Ece Toksabay; Writing by Daren Butler; Editing by Kevin Liffey