A Pakistani lawyer who received death threats for defending a doctor who helped CIA agents hunt Al Qaeda leader Usama bin Laden was shot to death on Tuesday by a Taliban splinter group, according to reports.

Samiullah Afridi represented Dr. Shakil Afridi, who was believed to have helped the U.S. intelligence agency track down bin Laden. Afridi was jailed in 2012 for 33 years for running a fake vaccination campaign. That sentence was overturned in 2013 and the doctor is now in jail awaiting a new trial.

According to police, Samiullah Afridi was shot dead as he was returning to his home in the northwestern city of Peshawar. He had recently returned there from abroad after leaving Pakistan for his safety, Reuters reported, citing local media.

The Pakistan militant group Jundullah, a splinter group of the Taliban, claimed responsibility. "We killed him because he was defending Shakil, who is our enemy," spokesman Fahad Marwat told Reuters.

Samiullah Afridi stopped representing the doctor last year, saying he had become a target. "I have been receiving threats from various organizations, and because of those threats I even went to Dubai some time back," he told Reuters TV.

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