The United States administration is pushing for greater control over the investigation of any involvement of the Pakistani spy agency Inter-Services Intelligence in slain al-Qaeda leader Osama bin Laden's presence in Pakistan since 9/11, amid fears that Islamabad may not carry out a credible probe.
US National Security Advisor Thomas E Donilon has asked that American investigators be allowed to interview the dead al-Qaeda chief's wives, who are in Pakistan's custody, The New York Times reported.
The large treasure trove of documents unearthed from bin Laden's house in Abbottabad, however, could lead to some clues on who inside the government and intelligence agency was secretly concealing his whereabouts.
The Times pointed out that the Bush administration had made a similar appeal to question Abdul Qadeer Khan, the chief of Pakistan's nuclear programme, who sold nuclear secrets to Iran, Libya and North Korea.
Islamabad, however, did not grant permission. "Our guess is that the wives knew just who was keeping Bin Laden alive for all these years," one official told The Times. "It's the Khan case all over again."
The newspaper pointed out that Obama administration did not expect Pakistan to carry out a credible investigation.
"For more than two years Pakistan has slow-walked investigations into the 2008 siege in Mumbai, India, by a terrorist group, Lashkar-e-Tayiba, that is believed to have strong links to portions of the Pakistani intelligence apparatus," it said.
The extent of official involvement in terrorist related activity, however, is not clear.
The Obama administration has stopped short of accusing the Pakistani government, which is Washington's ally in the war against terror. "But we don't know who or what that support network was," Obama told CBS news last week.
"We don't know whether there might have been some people inside of government, people outside of government, and that's something that we have to investigate, and more importantly, the Pakistani government has to investigate," he said.
Several observers in the US have pointed out that it may not be possible for Washington to cut its ties with Islamabad.
"It is hard to abandon Pakistan because of the danger of the nuclear programme and the need for help in counter-terrorism," Leonard S Spector, the director of the Washington office of the Monterey Institute's nonproliferation center, was quoted as saying by The Times.