CHANGCHUN - Customs police in Northeast China's Jilin province have recently busted a cross-border drug deal that utilized payment with bitcoin on the dark web, a new type of drug trafficking in China.

Changchun Customs said that on July 16, customs officers found a suspicious parcel delivered from Singapore. Ten boxes of suspicious pills were found in the parcel after examination, which were confirmed as tablets of tramadol hydrochloride later.

The customs launched an investigation into the case and arrested a suspect surnamed Zhang three days later. They confiscated about 1,237 tablets of tramadol hydrochloride, a medicine that is commonly sought by drug users.

Customs police said Zhang placed orders on the dark web -- part of the internet that requires specific software, configurations or authorization to access -- and paid with bitcoin to buy tramadol hydrochloride. Zhang purchased drugs from Singapore and Germany through this method before.

The purchased drug was then sent to China by post in parcels with a bogus customs declaration document.

Customs officers said purchasing drugs on the dark web using virtual currency is a new trend, which poses a challenge to the police.

Tramadol, which carries risks of physical and psychological dependence and has abuse potential, is a state-controlled nervous system drug in China.