Image copyright Police handout

Customs officials in Shanghai have arrested a woman attempting to smuggle two suitcases into China that were almost entirely made of cocaine.

Airport authorities X-rayed the luggage of a woman flying from an unnamed South American country.

The scan showed her luggage was darker in colour than normal, and also that it was unusually heavy even when it was empty.

Testing revealed the luggage was made of more than 10kg (22lb) of cocaine.

The incident took place in February but has only now been reported by the police.

Drug traffickers have long been dreaming up ways to transport cocaine - making an entire leg cast out of the drug, or dissolving it into wine, as one Chinese couple was caught doing just last month.

Hiding in plain sight

The usual ways would be to somehow hide the drugs within the luggage or on your body.

But constructing suitcases out of hardened cocaine and parading it in plain sight in front of security stands out as a first.

When the woman was asked to empty her luggage, there was nothing suspicious at first glance - merely an empty suitcase.

Image copyright Getty Images Image caption If that's how you think it looks, think again

What tipped the officers off was that it was significantly heavier than any empty luggage ought to be.

Compress and extract

There have been similar cases in Europe where smugglers used glue and moulds to compress cocaine into a hard substance.

Cocaine is a relatively rare drug in China, and the woman is expected to pay a heavy price for her attempt to bring it into the country.

Chinese law dictates that anyone convicted of trafficking more than 50g of cocaine will be executed.

It's the first time that this particular method of drug smuggling has been uncovered - yet it's unclear how many such suitcases might have passed under the eyes of unsuspecting airport security in the past.