Turkish authorities have confirmed the identity of one of the two suicide bombers responsible for the deadliest terrorist attack in the country’s history, Prime Minister Ahmet Davutoglu said Monday, according to Reuters. The attack outside Ankara's main train station on Oct. 10 killed 102 people and injured over 200 others.

An investigation into the identity of the second bomber is ongoing, Davutoglu reportedly said on Turkey's AHaber TV, adding that 15 people were detained in connection with the attack, four of whom had been remanded to custody.

Last week, police identified Yunus Emre Alagoz and Omer Deniz Dundar as the two suicide bombers, using DNA from the blast site. However, at this point it is unclear which one of the two men has been confirmed to be part of the attack. Authorities previously said that the bombings, which targeted a peace rally to call for an end to the renewed violence between Kurdish rebels and Turkish security forces, was linked to the Islamic State group, also known as ISIS. 

Alagoz was the brother of a 20-year-old man behind a deadly bomb blast in the southern Turkish city of Suruc in July that killed 33 people. According to a report Saturday, Alagoz owned a cafe where supporters of ISIS would often hang out, and he was already being sought by police as a member of an ISIS cell. Dundar was reportedly on a list of 21 suspected would-be suicide bombers.

Several days after the Ankara blast, Davutoglu said that authorities knew of potential threats but could not act without evidence of a planned attack. In a live interview on Turkish broadcaster NTV last Monday, Davutoglu said the attack was intended to "cast a shadow" over parliamentary elections on Nov. 1, and an attempt to influence its outcome.