The Interior Ministry identified the bomber as Saudi citizen Saleh bin Abdulrahman al-Qashaami in a statement carried by the official Saudi Press Agency late yesterday.
Al-Qashaami was wanted for being an active member of an Islamic State-linked terrorist cell, the ministry said. Lab tests showed that the explosive use in the bombing was a military-grade compound known as RDX.
The attack in the village of al-Qudeeh in the eastern Qatif region was the deadliest assault by militants in the kingdom since a 2004 al-Qaida attack on foreign worker compounds. It targeted members of Saudi Arabia's Shiite minority a sect that both the Islamic State group and ultraconservatives in Saudi Arabia regularly denounce as heretics.
The Islamic State's activities are primarily focused on Iraq and Syria. Its claim of responsibility for Friday's large-scale attack and the official Saudi confirmation bolster concerns that the group has established a toehold inside the oil-rich kingdom, as it has done in Libya and Egypt's Sinai Peninsula.
It has warned of more "black days" for Shiites in Saudi Arabia, a member of the US-led coalition that began targeting the group last year.