If you know the name moblin the hobgoblin find yourself heading out

I have a bandit who is part of a secret society as well as his main allegiance to his bandit group. The PCs are looking for a shop owner who's gone missing, and found a cloak belonging to the bandit group. The PCs know nothing about the group and my co dm is insisting that if interrogated, this NPC would be willing to give up information regarding the bandit group and that he's willing to help them fight the leader. I personally feel as they just met him, that this is too soon, and he would personally not give them any information until impressed by them later by events that will be taking place in town.

My co dm says that if bribed or threatened, he should just tell them everything. But I feel that it would ruin the flow of the game and send them into the heart of a bandit lair before they are ready to face the leader. They haven't even seen what the bandits do to town yet, this is their 2nd encounter with the bandits in any form.

Key information, anything that happens in this bar, the leader will know of, as he is in the bar as his common alias. The bandits do not know that their leader is in the bar, he is very secretive.

My bandit is working to take down the leader on his own, and will gladly take the party's help when he knows he can trust them to follow through, but I feel like an initial encounter would be a terrible start. "yea that's our cloak let's go kill my boss"

Any ideas on how I can withold any actual information but still make an engaging encounter?