He had been charged under a British-era regulation for frontier crimes that unlike the national criminal code does not carry the death penalty for treason. Under Pakistani penal law, he almost certainly would have received the death penalty, a Pakistani lawyer said.
Dr. Afridi's fate has been an added source of tension between Pakistan and United States, at a time when the two countries remain at loggerheads over reopening supply lines through Pakistan to Afghanistan.
In January, Defense Secretary Leon E. Panetta confirmed that the United States had been working with Dr. Afridi while trying to confirm the location of Bin Laden's compound in Abbottabad in the months before the raid. American officials had previously said that the doctor been running a hepatitis B vaccination program as a ruse to obtain DNA evidence from members of Bin Laden’s family, who were thought to be hiding in the city. American officials say Dr. Afridi did not know the identity of his target.
According to Pakistani security officials, Dr. Afridi admitted to helping the C.I.A. before the raid by Navy Seals that killed Bin Laden in May 2011. That operation angered Pakistani officials, who had not been informed ahead of time and who viewed it as a violation of the country's sovereignty.
Dr. Afridi, 48, was detained by Pakistan’s military intelligence agency near Peshawar in the weeks following Bin Laden's killing. A judicial commission in Pakistan investigating the circumstances leading to the death of Bin Laden had recommended in October that Dr. Afridi be charged with high treason.
American officials have said that while Dr. Afridi never gained DNA samples from inside the compound, his work aided the mission that led to Bin Laden's death. Secretary of State Hillary Rodham Clinton has called for Dr. Afridi to be released.
Mr. Panetta expressed anger in a television interview in January that Dr. Afridi had been charged with treason, insisting that the man's work in informing on terrorists helped protect Pakistanis, too. “For them to take this kind of action against somebody who was helping to go after terrorism, I just think is a real mistake on their part,” he said.