Syed Shoaib Hasan
BBC News, Islamabad
Mr Stanczak was abducted about 70km from Islamabad and beheaded
Police in Pakistan have arrested a former right-wing parliamentarian who is accused of ordering the murder of a Polish engineer by the Taliban.
Shah Abdul Aziz, who was arrested on Friday, is known for his close links to the Taliban and Islamic militants.
He had gone missing in May after allegedly being detained by security agencies.
The engineer, Peter Stanczak, was kidnapped by the Taliban in September 2008.
Mr Stanczak had been working on a project in the volatile north-west of Pakistan. He was beheaded by the militants in February after talks with the government for the release of captured Taliban members broke down.
Ataullah Khan, a Taliban militant, said in a confessional statement before a magistrate on Saturday:
"I kidnapped the Polish engineer with the help of Commander Tariq, Mufti Ilyas and others."
He was speaking in an anti-terrorism court in the northern garrison city of Rawalpindi.
"Later, we killed him on the orders of Shah Abdul Aziz after negotiations broke down."
Baitullah Mehsud is the leader of the Pakistani Taliban
Officials say Mr Khan clearly indentified Shah Abdul Aziz in court as the man who gave the order for Mr Stanczak to be killed.
Ataullah Khan was arrested on 16 July by the Islamabad police at a checkpoint on the outskirts of the city.
Police officials said a substantial number of arms and explosives were found in his possession.
He has since been in police custody.
During interrogation, officials say, he has confessed to being part of the Tehrik-e-Taliban Pakistan's (TTP) Darra Adam Khel wing led by Taliban commander Tariq Afridi.
He also admitted to having being involved in 50 murders, including that of Mr Stanczak, officials say.
Mr Afridi's group is held to be responsible for the kidnapping and murder of Mr Stanczak.
It operates under the larger aegis of Pakistan Taliban leader Baitullah Mehsud's TTP organisation.
Mr Aziz is known to have close links to Mr Mehsud and his organisation.
He had recently been trying to negotiate a peace deal between them and the Pakistan army.
The army is currently engaged in an operation in Baitullah Mehsud's South Waziristan stronghold.
Army officials say they were aware of Mr Aziz's efforts, but added the army was "not interested in dealing with miscreants".
In this regard, it is interesting to note that Mr Aziz was said to have been carrying a letter to Pakistan's army chief with a proposed outline of a peace deal.
Pakistan's top army spokesman, Gen Athar Abbas, had earlier denied the existence of such a letter, calling it "utter speculation".
But the most interesting aspect about this entire episode is that Mr Aziz had been missing since 27 May 2009 from Islamabad.
A police complaint in this regard had been registered on the same day by his friend, Khalid Khawaja, in Islamabad's Aapara police station.
Mr Khawaja had nominated police and security officials in his complaint, saying Mr Aziz was in government custody.
But the Islamabad police expressed their ignorance over Mr Aziz's whereabouts.
In fact, on 21 July, Islamabad police officials had submitted a sworn affidavit saying they had looked everywhere for Mr Aziz and could not find him.
"The government is implicating an innocent man," Mr Khawaja told the BBC.
"How can he have been arrested yesterday, when he was taken away two months ago.
"The Punjab government is guilty of gross human rights violation and illegal detention.
"They should first ask Mr Aziz where he was all this time before making such statements about him. "We intend to approach the supreme court on this matter."
The anti-terrorism court in Rawalpindi has given custody of Shah Abdul Aziz to the police for three days.
Mr Aziz is a former member of Pakistan's national parliament.
He was elected from the district of Karak in North West Frontier Province in the 2002 and subsequently lost his re-election bid in 2008.
Mr Aziz is a member of the right wing MMA political alliance.
The next hearing is to be held on 28 July.