Turkish security forces have detained a suspect wanted in connection with the deadly bombing in Istanbul in an operation in a Turkish-controlled area in northwestern Syria, Turkey’s state-run news agency reported.

Other suspects detained following the bombing will appear before court officials on Thursday to face possible charges or be released from custody.

The suspect, identified by his code-name “Husam” was apprehended by Turkish police late Wednesday in the Syrian city of Azaz, which is currently under the control of the Turkey-backed Syrian opposition, the Anadolu Agency reported. He was being taken to Istanbul for questioning.

His detention raised the number of suspects under custody in connection with the bombing to 51.

Sunday’s explosion targeted Istanbul’s bustling Istiklal Avenue — a popular thoroughfare lined with shops and restaurants — and left six people dead, including two children. Seven dozen others were wounded in the attack that came as a stark reminder of bombings in Turkish cities between 2015 and 2017, crushing the public’s sense of security.

Turkish authorities blamed the attack on the outlawed Kurdistan Workers’ Party, or PKK, as well as Syrian Kurdish groups affiliated with it. The Kurdish militants groups have, however, denied involvement.

Anadolu said “Husam” is suspected of aiding and abetting a Syrian woman who is accused of leaving a TNT-laden bomb at Istiklal. Police said the woman, identified as Ahlam Albashir, had crossed into Turkey from Syria illegally and has admitted to carrying out the attack.

Albashir and 49 others were taken to a courthouse in Istanbul on Thursday for questioning by court officials following routine medical checks, Anadolu said.

The PKK has fought an armed insurgency in Turkey since 1984. The conflict has killed tens of thousands of people since then.

Ankara and Washington both consider the PKK a terror group, but disagree on the status of the Syrian Kurdish groups, which have been allied with the U.S. in the fight against the Islamic State group in Syria.

Reuters