Gassed then burned. Why would you gas them if they are burnt to death already?
A thief snitched on them.
The trade exchanges had several positive affect on the city of Timbuktu. The city started becoming wealthy due to numerous trade exchanges. This wealth attracted many people from outside and made the city of Timbuktu very powerful. I hope that this is the answer that has come to your desired help.
Ensures government remains fair and accountable by creating checks and balances on the use of power. It is essential under the rule of law that the use of power is lawful, and can be challenged. Power is balanced between the Judiciary, Legislature and Executive, so each can act as a check on the power of the other.