Unidentified assailants have shot dead the former lawyer for a doctor who helped the CIA locate Al-Qaeda head Osama bin Laden.
Senior police officer Shakir Khan said Samiullah Khan Afridi was killed in Peshawar late on March 17 in the northwestern city of Peshawar.
The gunmen fled and police were hunting for them.
The militant group Jundullah, a splinter group of the Taliban, claimed they killing the lawyer because he defended the doctor.
Afridi defended Shakeel Afridi, who was sentenced to 33 years in prison in May 2012 for "conspiring against the state" after he was convicted by a Pakistani tribal court of having ties to militants.
A year later, a tribunal reduced his sentence by 10 years.
The lawyer left Pakistan in November 2014 after receiving threats from militants but returned recently.
