Medina mosque attack planner killed in shootout: Saudi officials
Interior Ministry Spokesman Major General Mansour al-Turki said Taya Sayari was killed on Saturday by police in the capital's northern Yasmeen neighbourhood.
The state-run Saudi Press Agency reported al-Turki's comments early on Sunday.
Islamic State group-link militant Talal Assaaedi was also killed in Saturday's shootout.
Both Sayari and Assaaedi were shot dead while trying to escape security officials in the usually quiet Jasmine district of Riyadh.
The July 4 bombing outside of the Medina mosque killed four Saudi security force members and wounded five.
Millions of Muslims from around the world visit the mosque every year as part of their pilgrimage to Mecca.
The same day, separate suicide bomb attacks targeted a Shia mosque in eastern Saudi Arabia and the US Consulate in Jeddah.