Islamabad: Pakistani police have questioned a 15-year-old boy detained as a suspect in the murder of opposition leader Benazir Bhutto.

The boy, identified as Aitzaz Shah, said that he was not in the town of Rawalpindi the day Bhutto was murdered.

"But he was part of the group that planned the assassination said one police official who asked not to be named.

The boy told investigators that had Bhutto survived the fatal December 27 attack he would have been assigned as the next suicide bomber to target her.

Sher Zaman, a second suspect, was also arrested on Friday while accompanied by Shah in a car driving along the Afghan border. Zaman is said to be the young boy's handler.

On inspection of the vehicle that the suspects were driving, police found explosives. According to Pakistani media, Shah is believed to have been assigned to target a nearby religious meeting by his handler, Zaman.

The arrest of Zaman is hailed as a major breakthrough in Bhutto's slaying. "He is the real catch,'' an official told Dawn newspaper.

Provincial police chief Azhar Ali Farooqi also said a five-person squad, headed by Al Qaida-linked militant leader Baitullah Mahsud was sent to target Bhutto. Mahsud's spokesperson denies these allegations.