Metin Ekinci is a brother of Azad Ekinci, who is accused of involvement in bombing attacks on HSBC headquarters, the British Consulate General and the Neve Shalom Synagogue in İstanbul in 2003.
Azad has been wanted in connection with the deadly attacks since then. His brother Metin's name was also mentioned in relation to the attacks as it emerged that one of the vehicles used in the attacks was registered in his name. Later, it was discovered that Azad had bought the car using his brother's ID card, which he had stolen.
Metin Ekinci joined Syrian opposition groups trying to topple President Bashar al-Assad in July, according to media reports.
Joining a group of 23 Syrian rebels fighting the Assad regime, Ekinci was one of those involved in the killing of post office clerks and security officers by throwing them down off the roofs of buildings in the town al-Bab in Syria, the Turkish daily Hürriyet said.
Syrian state TV reported that Ekinci was killed together with other group members during a clash between regime forces and rebels on Tuesday. Metin's ID, as well as footage of his dead body, was shown on the channel. There was no statement from Turkish officials regarding his death.
Osman Karahan, the Turkish lawyer of the al-Qaeda members who are suspected of carrying out the İstanbul attacks, was also killed during the clashes in Aleppo earlier this month.