In the months before Osama bin Laden was [allegedly] killed, the Central Intelligence Agency ran a phony vaccination program in Abbottabad, Pakistan, as a ruse to obtain DNA evidence from members of Bin Laden's family thought to be holed up in an expansive compound there, according to an American official. The vaccination program ... adds a new twist to the months of spy games that preceded the nighttime raid in early May. It has also aggravated already strained tensions between the United States and Pakistan. The operation was run by a Pakistan doctor, Shakil Afridi, whom Pakistani spies have since arrested for his suspected collaboration with the Americans. Dr. Afridi remains in Pakistani custody, the American official said. Obama administration officials have said publicly they were not sure whether Bin Laden was in Abbottabad when dozens of Navy Seals commandos stormed the house in May. Pakistani military and intelligence operatives were furious about the American raid ... and relations between the United States and Pakistan have only plummeted since. Pakistani officials have suggested that they might use troops to repel another incursion into Pakistan.