Pakistani investigators are questioning a teenager who confessed he was “next in line” to kill former premier Benazir Bhutto if other militants involved in her assassination last month had failed.

Aitzaz Shah, 15, who was arrested with another militant named Sher Zaman in Dera Ismail Khan town in North West Frontier Province (NWFP) on Thursday, has told investigators he was trained as a suicide bomber and was part of a five-man squad sent by Tehrik-e-Taliban Pakistan commander Baitullah Mehsud to kill Bhutto.

Security personnel also raided Shah’s home in Battal area of Mansehra district of NWFP this morning, officials said.

This were the first arrests made in the probe into the assassination. Interior Secretary Syed Kamal Shah has confirmed that two people were arrested in Dera Ismail Khan and one of them, a teenage boy, had confessed to involvement in the attack on Bhutto.

However, a spokesman of Baitullah Mehsud on Saturday denied that the Taliban commander had any links with Shah, saying he had not been tasked by the militant group operating in South Waziristan tribal agency to carry out any attacks. Spokesman Maulvi Muhammad Omar described Shah’s confession a part of “government propaganda” and said Mehsud had already said he had nothing to do with the attack on Bhutto.

“We have denied our involvement in Benazir’s assassination before and are strongly denying this again. We are not involved in Benazir’s murder,” Omar told reporters in Tank town near Dera Ismail Khan. “On Saturday, the American CIA made a similar claim and now the police claim seems to be a continuation of the same conspiracy.”