Investigators in Pakistan examined the remains of a suicide bomber who targeted police in Lahore Thursday, killing at least 22 people.
A spokesman for the interior ministry said the bomber's head and limbs found at the blast site are being tested to determine his identity.
No group has claimed responsibility but government officials blamed al-Qaida-linked militants operating in Pakistan's tribal region.
The attacker walked up to a group of policeman gathered outside the High Court in Lahore ahead of a planned rally and set off explosives. Most of the dead were policemen and scores of other people at the scene were wounded.
The attack came exactly two weeks after the assassination of opposition leader and former Prime Minister Benazir Bhutto.
Hundreds of people have been killed in a wave of suicide bombings in Pakistan over the past year.
Some information for this report was provided by AFP and Reuters.