Candy cane robber

Logic Level 1

In a candy-land a robber stole a precious candy cane! The chocolate detective comes down to some solutions. The chef, the butler, the prince and the maid.

The chef says: The maid did it!
The butler says: I did it!
The prince said : The chef is lying!
The maid said : I didn't do it!

If only one of them is telling the truth, who stole it?