I'd be checking the gold and silver villages Celuk and Mas. Wonder if he took stolen gold and silver jewellery to be minted into rare coins.

Celuk Village - Bali.com
Celuk Village is actually an area located along the street of Jalan Raya Celuk near Ubud - Sukawati. It is very famous for its silver & gold handicrafts, in particular jewellery, there are many silver & gold galleries lining on both sides of the road.