ISLAMABAD (Reuters) - Pakistans powerful military and its spy agency must have been aware Osama bin Laden was hiding in the country and avoided telling critical ally the United States to protect its strategic assets, a leading authority on the army said. Somebody in a position of authority had to know, said Ayesha Siddiqa, author of Military Inc. In an interview with Reuters, Siddiqa reviewed many factors she said would have made it inconceivable for the worlds most-wanted man to live in Pakistan undetected by the army and its ubiquitous Inter-Services Intelligence (ISI) agency. An ordinary writer like me - our phones are tapped, our emails get probed into. So how come nobody was looking into Osama bin Laden being there? asked Siddiqa. It seems less plausible that people didnt know. Logic alone, she said, proves her point. Just 10 days before US Navy SEALs killed bin Laden in the city of Abbottabad on May 2, the army chief gave a speech at a nearby military academy on how the military had broken the back of terrorists. The army chief is the most powerful man, the king in the Pakistani national narrative. He is the equivalent to what a king would be in Saudi Arabia or somewhere else, said Siddiqa, adding that the area must have been swept by security forces before the event. Siddiqa, speaking in a coffee shop at a shopping arcade where Punjab Governor Salmaan Taseer was killed by his bodyguard in January, said that once again the armys obsession with rival India had backfired. She argued that the army and ISIs strategy against India may have been why the security establishment turned a blind eye to bin Laden, possibly regarding his network as an asset. To them, there were no other options to deal with the perceived threat from fellow nuclear power India, she said. Nuclear weapons we know are deterrents. You cannot use them. Conventional strength? We dont have sufficient conventional strength ... That leaves one possibility, which is using sub-conventional defence, which is non-state actors (militants), she said. That is where the problem lies. Nevertheless, Siddiqa says, the generals may have calculated that keeping ties with militants, even US enemy number one bin Laden, was a tactical must. Officials looking for damage control over the presence of bin Laden in Pakistan by some accounts for more than 7 years may suggest that it was rogue ISI agents or retired army officers who protected bin Laden. Siddiqa doesnt buy that argument. It has to be active duty people. Some of them had to know, she said, adding that al Qaedas ties with anti-Indian militant groups may have persuaded them that keeping bin Laden in Pakistan was worth the risk of angering the United States.