Who was responsible for the Istanbul attack?

Bomber was pregnant

ISTANBUL - Uncertainty grew on Thursday over the identity of a female suicide bomber who attacked the heart of Istanbul's tourist district, after reports she was a Russian national from the Caucasus contradicted a previous claim of responsibility.
Banned far-left Turkish militant group DHKP-C initially claimed the Tuesday attack that killed the bomber and one policeman in Istanbul's Sultanahmet district. It also named the bomber as Elif Sultan Kalsen.
However doubts were raised when Elif Sultan Kalsen's mother Sirin was taken to identify the corpse and said it was not her daughter, Turkish media said.
Turkish Interior Minister Efkan Ala then announced early Thursday that the "identity (of the bomber) had been determined" and that the investigation had made great progress.
But he said if would not be "correct" at this stage to give further details, declining to give the identity of the bomber, the official Anatolia news agency reported.
Turkish private news agency DHA, without giving its sources, said the bomber had been named as Russian citizen Diana Ramazova from the Russian region of Dagestan.
The conclusion was based on evidence found on a mobile phone at the scene, DHA said. It said an autopsy had also determined that she was pregnant.
She was now being investigated for any links to Al-Qaeda and the Islamic State (IS) militant group, it said. She had entered Turkey as a tourist seven months ago.
Dagestan, a mainly Muslim region in the Caucasus mountains on the Caspian Sea, has in recent years been fighting a deadly anti-Kremlin insurgency waged by Islamist militants.
The 2010 suicide bombings on the Moscow metro that killed over 40 people were carried out by two women from Dagestan.
The 2013 attack on the Boston marathon was also perpetrated by two Russians of mixed Chechen-Dagestan ancestry who had spent part of their youth in Dagestan.
The Marxist Revolutionary People's Liberation Party-Front (DHKP-C) had said Wednesday that its "sacrificial fighter" Elif Sultan Kalsen had carried out the suicide bombing.
It said that the bombing was a "bringing to account" for the ruling Justice and Development Party (AKP) co-founded by President Recep Tayyip Erdogan over alleged corruption.
But the group on Thursday removed the statement claiming responsibility from its website without giving any explanation.
The DHKP-C has carried out suicide bombings in the past -- it claimed a suicide bombing in February 2013 at the US embassy in Ankara where a security guard was killed.