Turkish prosecutor taken hostage in Istanbul
Dramatic images have emerged on social media of a gun being held to the head of Mehmet Selim Kiraz at a court house in Istanbul.
A banned Marxist revolutionary group is suspected of being behind the incident.
A statement posted online said the prosecutor would be killed if their demands were not met.
Turkish special forces entered the court house, which was evacuated, and gunshots were heard from inside the building, Turkish news agencies reported.
City police chief Selami Altinok told reporters that negotiations with the hostage takers were under way.
Berkin Elvan, who was then 14, was struck in the head by a police tear gas canister in June 2013 as he went to buy bread during mass demonstrations that began in Istanbul and spread across Turkey.
After nine months in a coma he eventually died in an Istanbul hospital.
Suspected members of the Revolutionary People's Liberation Party-Front (DHKP-C) took the prosecutor hostage on the sixth floor of the Caglayan court house, reports said.
A website close to the group has published a series of demands, including calls for an immediate confession from police officers responsible for the boy's death, and for an end to prosecutions of protesters charged over the clashes.
Berkin Elvan's father appealed for the prosecutor to be freed: "My son is dead but let no-one else die."
"You can't wash blood with blood," he told BBC Turkish.
Turkey's prime minister met the interior minister to try to defuse this latest crisis, the BBC's Mark Lowen in Istanbul reports, for full story go to BBC.com
