A long term captivity sounds a bit problematic. It would be definately best, but I don't know if other cops are willing to go along with it.
Also. A promise for a cut of the winnings is a great motivator along with the promise of actually making it out alive. People will do anything if there's even a glimmer of hope.
Also Cardamine does unexpectable things to morality. Especially if your daily dose is missing.
