Hehehe, we don't know anything yet. What Salhuddin knows is justification for wariness, but we don't know the specifics here. A jann raider could be magically bound for example, and not currently a threat to anyone. Or he could be the real ringleader here, and the women and children ensorcelled human shields. Or anything in between.
Best to stay alert, make some insight checks (which I need to do actually), and keep our wits about us. There are oddities afoot.
Like...the Jann lost his water, right? And the hydra guards the pool. And travelers stopped coming.
...so where are they getting water from?