If I were you, I will call the police first. At least, in front of the 2nd maid, she knew that you realized something lost and you will call police and ask for fingerprint.
If there is another fingerprint found on your jewellery box, then should be the 1st one ar...(then you can ask your relative to be careful and keep an eye on your 1st maid ma!!)
Bun BUn and Yan Yan goe to pawn shops is suspcicous, yes. However, my sister's maid also visited pawn shop before. She sold HER ring not my sister's becasue of her debt from the bank...