[Radek]

Thieves in the game:

1. Every thief class (rogue, ratling (i.e., ninja), troll sneek, etc.) can attempt to steal from you.

2. If the thief steals an item then the item is dropped on the ground when the thief gets killed and you can get the item back. Note that the thief can steal everything including quest items or keys. Always check the ground after fighting thieves. Always check your inventory after such fight, if you are bearing some valuable items or quest items.
Summary: You can always get all stolen items back.

3. If the thief steals money then the money is LOST FOREVER. The thief will not drop it after being killed. Moreover, the thief steals ALL your money at once. More precisely, all money of the attacked character in your party.
The only defense is: NEVER TAKE YOUR MONEY OUT OF A TOWN. You will never need your money in the wilderness!
a) The few traders in the wilderness can offer you nothing. You need not money there.
b) There is only one bank in Gael Serran. If you place your money to the bank in Valeia, you can take the money out of the bank in Ishad N'Ha and so on. In the other words, there is no need for transporting money from one town to another.