Terrorist groups sometimes claim "credit" for doing things they had no part in. For example, several years ago a Lauda Air airliner (an airline owned by racing great Niki Lauda) came apart in midair and crashed in Thailand, killing 223 passengers and crew. At least one terrorist group claimed credit for putting a bomb on the plane. However, the accident investigation proved that it was a freak mechanical malfunction - one of the thrust reversers deployed in flight - not a bomb that downed the plane.

I can see how a terrorist group would like to be able to point to potential recruits and say "we did that" as a means of showing how powerful they are. Just in case and in the name of thoroughness, I say kill them all.

Date: 05/26/1991
Location: Ban Nong Rong, Thailand
Airline: Lauda Air
Aircraft: Boeing 767-300ER
Registration: OE-LAV
Fatalities/No. Aboard: 223:223
Details: Twelve minutes after takeoff the crew received a visual REV ISLN advisory warning which indicated that an additional system failure may cause deployment of the No. 1 engine thrust reverser. No action was taken since the manual indicated "No Action Required". Just before reaching FL 310 during a climb, there was an uncommanded deployment of the No. 1 engine thrust reverser. The aircraft stalled, when into a steep high speed dive, broke apart at 4,000 feet and crashed into the jungle. Failure of the reverse thrust isolation valve. Following the accident Boeing made modifications to the thrust reverser system.