The suicide bomber who blew himself up outside the US embassy in Ankara was an ex-prisoner who suffered from a brain disorder triggered by going on hunger strike, local media and officials said Saturday.
Officials identified the bomber as Ecevit Sanli, 40, suspected to be a militant from an outlawed leftwing group that has recently faced a crackdown by the Turkish authorities.
He detonated a hand grenade and about six kilogrammes (13 pounds) of TNT in Friday's blast, the Ankara governor's office said in a statement.
A Turkish security guard was also killed in the attack, and three other people were wounded.
Authorities said the bomber was a member of the Revolutionary People's Liberation Front (DHKP-C), a radical leftwing group blamed for several attacks since the late 1970s including suicide bombings and attacks on prominent figures.
Sanli had been jailed after a 1997 attack at a military compound in Istanbul and released in 2001.
Interior Minister Muammer Guler told journalists that Sanli had left Turkey after his release from prison and recently returned to the country using false papers. Guler said Sanli had been sought by the authorities.
While in detention, he had participated in a hunger strike and as a result suffered from Wernicke-Korsakoff syndrome, a brain disorder caused by thiamine deficiency, local press reported on Saturday.
He was chosen for the suicide attack because "his days were numbered," according to the dailies Milliyet and Vatan.
Another newspaper, the Radikal, however, said that the organisation normally forbids seriously ill members from carrying out such attacks.
Turkish authorities have not yet made any arrests in the attack.
Turkish news agency Anatolia broadcast security camera footage of the attacker arriving alone, carrying a parcel in his hands.
Turkey last month carried out a major nationwide crackdown on the DHKP-C and arrested about 100 people, including lawyers and musicians suspected of ties to the group.
DHKP-C is vehemently anti-US, anti-NATO, and anti-Turkish establishment.
Turkish Prime Minister Recep Tayyip Erdogan has said the group was responsible for the attack, but it has not yet claimed responsibility.