Xiao Yuan's case was exposed when someone found an official stamp of Guangzhou Academy of Fine Art on an item for auction in Hong Kong. The person had doubts and called the police.

Dong Guoqiang explains that such items are common at auctions.

"It is ordinary to see an official stamp on a painting for auction. Such cases are not rare. You cannot jump to the conclusion that the item was stolen from certain institution merely based on a stamp. "

Ma Weidu, the ntiques collector, warns auction companies to stay alert.

"When one person has a lot of paintings sealed with official stamps, auction companies should be alert. Sometimes, the verification is very simple, you can just make a phone call."

Xiao has already pleaded guilty. The court is yet to hand down a sentence.