Image caption Osama Bin Laden was killed by US operatives in Pakistan on Sunday

A 2008 study conducted by US university professors suggested there was a high probability Osama Bin Laden had taken refuge in the town where he was ultimately killed by US operatives on Sunday.

The model employed in the study, which is typically used to track endangered species, said there was a 88.9% chance he was in Abbottabad in Pakistan.

But geographer Thomas Gillespie at UCLA said the same study gave a 95% chance he was in another town, Parachinar.

The findings were published in 2009.

Mr Gillespie, whose expertise is in using remote sensing data from satellites to study ecosystems, initially conducted the study with undergraduate geography students as an exercise in 2008 and submitted its findings to the MIT International Review in 2009.

The probabilistic model used in the study pinpointed Parachinar, which is roughly 300km (186 miles) from Abbottabad, as having a 95% likelihood of being the town where Bin Laden was hiding out.

Mr Gillespie and his students took the findings and then zeroed in on Parachinar because it also had access to medical care.

But the study also gave Abbottabad, where Bin Laden was shot and killed on Sunday by US forces, an 88.9% of being the al-Qaeda leader's hide-out.

The model, which Mr Gillespie typically uses in his work to track endangered species, suggested Bin Laden was probably residing in a city compound, rather than in a cave in a rural environment, because people in less densely populated regions would be more likely to take the time to notice him, the university professor told the BBC.

Using the study, Mr Gillespie and his students then surmised that the compound would have security, such as high walls around its perimeter, and an electricity supply, both of which were found at the site of Bin Laden's residence in Pakistan.