Complex sentence: He was a member of Abu Nidal group of three people, remaining two hijackers were killed, either in in-flight shooting with a sky-marshal or after Egyptian commandos stormed the hijacked plane.
Split into simpler sentences: He was a member of Abu Nidal, a group of three people. The remaining two hijackers were killed, either in in-flight shooting with a sky-marshal or after Egyptian commandos stormed the hijacked plane.