Rescuing People's Money from Thieves

There is a gang in a town that steals from people, and their danger has become severe. There are no security forces in that town, and one of the people knows their hideout and where they keep their loot. Is it permissible for this man, who knows their hideout, along with some brave men, to take this money secretly from them, identify it or identify its owners, and send it to the owners? Or is this secret taking considered theft as well?
If a man sees stolen money and knows its owner, it is obligatory for him to rescue it from the thief. If these men go to the hideouts of these thieves and take the people's money to return it to the people, they are doing a great good and will receive a great reward. Let them do so as much as they are able.