The identity of the bomber was revealed by a DNA test, the anonymous sources confirmed, adding the DNA samples provided by Somer's father matched the assailant's, Xinhua news agency reported on Wednesday.
Somer's father, who lives in the eastern province of Van, had informed police that his son was behind the attack.
Abdulbaki Somer, born in 1989, was listed as a missing child in the Turkish police's records, the Hurriyet daily reported on Tuesday.
The report said Somer had gone missing in August 2005 in Van. His parents informed the police and also said some of his friends had joined the terrorist Kurdistan Workers' Party (PKK).
Somer had joined the PKK after his disappearance, and went to the organization's camps in northern Iraq where he was trained for 8 years, the report said.
He returned to Turkey in 2014 and registered himself with the state as "Salih Muhammed Neccar", according to Hurriyet.
The car bombing attack in the Turkish capital on February 17 had claimed 29 lives, leaving 60 others wounded. Currently, 14 suspects are in custody.