PESHAWAR, Pakistan — A Pakistani doctor who helped the CIA find Osama bin Laden has been charged with murder over a 2006 surgery he performed, his lawyer said Friday, raising new doubts whether the physician will regain his freedom.

Shakil Afridi already is being held in prison pending retrial on a separate charge, despite U.S. officials demanding he be released. The case has caused friction between Pakistan and the U.S., complicating a relationship that Washington views as vital for fighting the Taliban and al-Qaida, as well as negotiating an end to the war in neighboring Afghanistan.

The murder charge stems from a complaint over a teenage boy who died after Afridi performed surgery on him for appendicitis in 2006.

The complaint, filed by the deceased teenage boy's mother, Nasib Gula, says Afridi was not authorized to operate on her son because he was a physician, not a surgeon, said the doctor's lawyer, Samiullah Afridi. The boy died from complications following the surgery, which took place in Pakistan's remote Khyber tribal area, the lawyer said.

The lawyer, who is not related to his client, said the case had no merit because too much time had passed since the incident. The trial has been scheduled for mid-December, he said.

The doctor is currently being held in prison. He was convicted of "conspiring against the state" in May 2012 and sentenced to 33 years in prison. His conviction was related to allegations that he gave money and provided medical treatment to Islamic militants in Khyber, not for helping the CIA track down bin Laden. The doctor's family and the militants denied the allegations.

A senior judicial officer overturned the prison sentence and ordered his re-trial in August, saying the person who sentenced the doctor was not authorized to hear the case.

Afridi's situation has sparked widely divergent views inside and outside of Pakistan.

In the U.S. and other Western nations, Afridi was viewed as a hero who had helped eliminate the world's most wanted man. The doctor ran a vaccination program for the CIA to collect DNA in an attempt to verify the al-Qaida leader's presence at the compound in the town of Abbottabad. U.S. commandos later killed bin Laden there in May 2011 in a unilateral raid.

Pakistani officials were outraged by the bin Laden operation, which led to international suspicion that they had been harboring al-Qaida's founder. In their eyes, Afridi was a traitor who had collaborated with a foreign spy agency in an illegal operation on Pakistani soil.

Also Friday, a pair of bombs exploded in the southern city of Karachi, killing five people and wounding 19 others, hospital official Abbasi Shaheed said. No group immediately claimed responsibility for the attack.