Chinese consular records should show what visas were issued, since a holder of either of the stolen passports would require a visa and we may assume that MAS ground staff would have checked that the visas were in order.
You DO NOT have to have a valid visa to enter China if you are a transit passenger with an on-going ticket to another country. You can stay in China for 72hrs.
The e-ticket photo supplied shows an on-going ticket to AMS, (KUL-PEK-AMS) which would match up the theory of whom-ever having no intention of setting foot in China at all.
Get your facts straight.