WASHINGTON – One of Osama bin Laden’s sons have been killed by a US missile strike in Pakistan earlier this year, National Public Radio reported. Saad bin Laden, the Al-Qaeda leader’s third-oldest son, is “believed” to have been killed by Hellfire missiles fired from a US Predator drone “sometime this year,” the US broadcaster said on its website.The United States has put Pakistan at the heart of the fight against Al-Qaeda. The US military and the Central Intelligence Agency (CIA) are the only forces that deploy drones to the region.US spy agencies are “80 to 85 percent” sure that Saad bin Laden is dead, a senior counterterrorism official told NPR, while acknowledging that it was difficult to be completely sure without a body on which DNA tests could be conducted.Officials at the CIA and the US Central Command, which oversees US military operations in the Horn of Africa, the Middle East and Central Asia, told AFP they could not immediately confirm the report.