Even as United States officials pick apart the treasure trove of intelligence information collected at the Abbottabad compound where al-Qaeda leader Osama bin Laden was killed on Sunday night, there are some unanswered questions about the biggest piece of evidence on site — Osama's “mansion.”

Comments by Pakistani intelligence officials and Pakistani President Asif Ali Zardari on the one hand, juxtaposed with comments by John Brennan, White House Security and Counter-terrorism Adviser, beg the significant question: In whose name was the compound registered, and if Pakistani officials knew it belonged to a suspicious “foreigner” then why was that not investigated immediately?

According to statements made by an unnamed official of Pakistan's Inter-Services Intelligence to a reporter from the BBC, the compound in Abbottabad “had been raided in 2003” but was “was not on our radar” since then.

Further, a statement released by the Pakistani Foreign Office said that Abbottabad and the surrounding areas were “under sharp focus of intelligence agencies since 2003” and the intelligence flow indicating some foreigners in the surroundings of Abbottabad continued till mid-April 2011.

While the Pakistan FO indicated that as far as the target compound was concerned, the ISI was sharing information with the U.S.' Central Intelligence Agency since 2009 and Mr. Zardari said Pakistan's “early assistance in identifying an al-Qaeda courier ultimately led to” Osama's capture, Mr. Brennan's comment on the compound would appear to challenge these assertions.

When asked, at a press briefing here on Monday, about who owned the land, Mr. Brennan said: “Whether it be the land or the compound, but it was two of the individuals who were killed — the al-Qaeda facilitators, as they are called — the individual who was identified as the gatekeeper courier, the residence was, at least in my understanding, in his name.”

While there is a lack of clarity on whether one of the couriers, said to be named Sheikh Abu Ahmed, owned the land or the building on the site, if Mr. Brennan were right, an explanation would be required as to how the very same courier could register such a large property with 18-foot walls literally on the doorstep of a major military facility and under the nose of the ISI.

Indeed there have already been calls for an explanation in this regard with one regional expert, Lisa Curtis of the Heritage Foundation, saying, “There needs to be an accounting from Pakistan on how the world's most wanted terrorist could hide in plain sight at a large and conspicuous compound in a Pakistani city that is home to one of Pakistan's most prestigious military training facilities.”

Mr. Brennan also hinted at a similar question saying, “People have been referring to this as hiding in plain sight... We are looking right now at how he was able to hold out there for so long, and whether or not there was any type of support system within Pakistan that allowed him to stay there.”