Man caught ‘smuggling four gold bars up his rectum’ How did he do it

How did the authorities notice him? Apparently he was ‘walking suspiciously’, the BBC reported.
A total of 400g of gold in the form of four bars was allegedly found inside the Sri Lankan man’s rectal cavity after he was searched by security at Bandaranaike International Airport.

More than 70 people have been arrested this year for trying to smuggle gold bullion by Sri Lankan officials.
They say the smugglers usually buy cheap gold in Dubai or Singapore before trying to make their way to India in order to sell the gold for a profit.
Presumably the buyers are ignorant of the gold’s transit conditions.