The Track and Capture Criminals skill can be learned from a chest inside Knotwood Jail at 43, 30. With this skill you will find you now have the option when clicking on a (humanoid) monster or player with a bounty to Capture them.

In doing so you will claim a small bounty for monsters or whatever the bounty is for that specific player.

Players who have a bounty are sent to Jail for a minimum of 15minutes. While in Jail they can either choose to sit their sentance out or try to find a secret tunnel out of the Jail to cut it short.

This skill is normally used with Detect Hidden as most players with a bounty are usually stealthed.