The interior ministry confirmed that 15-year-old Aitzaz Shah had been arrested in the northwestern city of Dera Ismail Khan last week. He confessed that he was a member of the backup 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 the police for interrogation. Another suspect, Sher Zaman, was also arrested on a tip from Aitzaz Shah, according to officials. Aitzaz Shah has identified the bomber as Bilal, who belongs to South Waziristan tribal region, TV channels said.Media reports said that investigators showed the picture of the bomber to Aitzaz Shah, who recognised him.

TV channels reported that a team of investigators had left for South Waziristan to meet members of Bilal's family to get more information about him. Bilal was a member of the Baitullah Mehsood group, blamed by the authorities for organising suicide bombings against security forces across the country.

The interior ministry had released a videotape a day after the assassination of Bhutto in which two persons identified Bilal as among the bombers who killed the former prime minister.