CAIRO – As Egyptians try to recover from the massacre at a northern Sinai mosque that left 305 dead, the area's tribal leaders swore blood-feud revenge on Sunday against those behind the coordinated attack.No one has claimed responsibility for Friday's bombing and assault, but Egyptian law enforcement officials believe the Islamic State-Sinai Province, a 6-year-old terror cell that swore allegiance to the Islamic State, was responsible.
