First time I’ve heard of a man being stoned to death by ISIS.

(Reuters) – Islamic State militants in Iraq stoned a man to death in the northern city of Mosul after one of their courts sentenced him to die for the crime of adultery, a witness said on Friday.

The stoning, which happened on Thursday, was the first known instance of the punishment by al Qaeda offshoot Islamic State militants in Iraq, although it had been reported previously in Syria.

Members of the hardline Sunni group, which seized Mosul in June and also controls swathes of territory in neighboring Syria, have shot, beheaded and crucified prisoners and blown up and bulldozed Shi’ite mosques.

The United States began air strikes on Islamic State positions in Iraq this month, and in retaliation the group published a video of one of its black-clad fighters beheading U.S. journalist James Foley.

A taxi driver who said he saw Thursday’s stoning in Mosul said he stopped to find out what was happening when he noticed a crowd gathering and about 20 Islamic State vehicles parked nearby.

Some militants were gathering sharp pieces of rock while another held a video camera, he said.

Eventually, the militants brought a handcuffed young man from one of the vehicles, made him sit down on the ground, and began pelting him with rocks, the witness said. Some in the crowd turned away as the man cried, “I did nothing,” he said.