The SAS's intervention has allegedly angered Libyan opposition figures who ordered the armed and plain-clothes soldiers to be locked up on a military base.
If you're not in uniform you are a spy. They are in their rights to execute them.
I am not so sure they are. Are the the captors of them a legitimate and recognized force?
I agree with you if they were captured by an armed force of a country during a battle.
I am not so sure the people doing the capturing are a legit force.
Either way I think they would do best by not executing them.