Nasty way to go. Many times not immediate death. Lungs fill with fluid. Kind of like pneumonia.
Notice how quiet the media is about this.
Sounds like the gas was used to immobilize then a bomb used to blow them up.
Chlorine gas is nasty stuff. If you have a pool and mix powder with water it can explode if you have mix 2 incompatible granular bases. Sent me to the ER.
It happens a lot when people try to shock a pool through the tablet dispensers.