A 15-year-old detained near the Afghan border has confessed to joining a team of assassins sent to kill Benazir Bhutto, officials said Saturday, announcing the first arrests in the case since the attack that killed the opposition leader. Interior Secretary Kamal Shah confirmed the arrest of two people in the town of Dera Ismail Khan in North West Frontier province, and said one -- a teenage boy -- had confessed involvement in the December 27 attack that killed Bhutto. He said interrogators were trying to get corroborating testimony from the other detainee before accepting the confession, according to a report of the Associated Press.