The interior ministry confirmed that a 15-year-old boy named Aitzaz Shah had been arrested in the northwestern city of Dera Ismail Khan last week. He confessed that he was a member of the back-up group of suicide bombers who killed Bhutto.

Aitzaz Shah was later shifted to Islamabad for questioning and a court has given his 10-day custody to police for interrogation. Another suspect Sher Zaman was also arrested at a tip from Aitzaz Shah, according to officials.

Aitzaz Shah has identified the bomber Bilal, who belongs to South Waziristan tribal region, according to local TV channels.

Reports said that investigators showed the picture of the bomber to Aitzaz Shah who recognized the suspected bomber as Bilal.

TV channels reported that a team of investigators had left for South Waziristan to meet family members of Bilal to get more information about him.

Bilal was a member of Baitullah Mehsood group, blamed by authorities for organizing suicide bombings against security forces across the country.

There was no official confirmation of the reports.

The Interior Ministry had released a video tape a day after the assassination of Benazir Bhutto in which two persons said Bilal was among the bombers who killed Benazir Bhutto.

The police have also arrested six persons in different parts of Rawalpindi in the light of information provided by Aitzaz Shah.

Benazir Bhutto was killed in firing and suicide bombing attacks in the garrison city of Rawalpindi on Dec. 27 after she addressed an election rally.

The interior ministry blamed Baitullah Mehsood for the killing of Benazir Bhutto. However, a spokesman of Mehsood denied the accusation.