The Philippines military has released footage of the person suspected of detonating a bomb that killed 21 people on Sunday.
Known by the alias Kamah, he's believed to be a bombmaker and the brother of the former leader of the Abu Sayyaf terror group.
In the clip, the man is seen running away from the scene of the attack on a church in Jolo while holding a mobile phone, which officials believe may have been used to detonate the device.
At least 80 other people were injured when an explosion inside the building was followed by a second just outside.