Not just torturing, but from the sounds of Sylvia's plan, slaughtering the prisoners after they've given up everything they know
+EDIT
To summarize the current plans that seem to be floating around so far:
1. Let the bandits take the stuff and follow them back to camp, then fight down the camp, attempting to kill a couple bandits at a time.
-Ortlieb is reasonably confident he could track a mounted group of bandits not hiding their trail.
-Plan banks on being able to kill the entire camp either without them mustering in force against you, or being able to fight the entire camp (not wanting to fight the entire camp being one of the reasons why the tax collectors would be allowed to go)
2. Capture the hooded bowman who seems to hold a certain elevated position, and capture/kill his cohorts. Extract information out of the captives as to location of the camp and whatever other details may come to mind, using increasing levels of persuasion as necessary. Sylvia's version: slaughter the captives after they spill the information. Sordin's version: offer captives a chance to redeem themselves and turn away from banditry; if they refuse, the penalty for unrepentant banditry is execution (note how much more official 'execution' sounds than 'slaughter').
-Bandits, theoretically, may withhold information. PCs' Moral fibre may prevent the more extreme methods of information extraction.
Other details:
-It's not known how long the camp would take to retaliate for the missing tax collectors. Also, the full extent of the bandits' forces unknown; placed at twelve minimum, assuming no deaths or departures in the last 3 months.
-Likelihood is that the tax collectors are not expecting any resistance, and so would be easy to ambush.
-Ortlieb probably
could backtrack the taxmen's original approach, should they all die/prove unhelpful.
-Oleg has been sending messages to the city requesting guards for months now. His request has been recently approved, though when they will arrive is up to the bureaucratic BS, which is how the message concerning your arrival came to imply you could help with the problem until the guards arrived.