Three South Korean tourists were killed and more than a dozen injured after their bus was bombed in Egypt on Feb. 16.

The American Spectator reports that the tourists were all Christians from the same church and had just visited a popular monastery. The motive for the attack is unknown.

The Spectator cites Egyptian authorities as believing that an Islamist group, Ansar Beit al-Maqdis, was responsible, although no-one has claimed responsibility.