A foreign man, who claimed to be a journalist, was detained by Beijing Customs after they discovered heroin inside his sports shoes at Beijing Capital International Airport.

The alleged smuggler, whose identity and nationality have not been revealed, arrived in Beijing at 8 am on January 11. He told the customs officer he had nothing to declare, and being a reporter, he would stay in Beijing for a long time. It is not known where he boarded his flight.

"However, this self-declared reporter had no journalist visa which made him suspicious," said a press release from Beijing customs. The suspect only had a small carry-on and a laptop bag, which contained no camera or other equipment.

Feng Lijing, media officer from Beijing Customs, said  that when they X-rayed the suspect's belongings, they saw there were suspicious shadows in the shoes he was wearing.  

"When our staff took the insoles out, we found two bags of white powder, which weighed 680 grams and was later proved to be heroin," Feng said.

The suspect is detained and officers are working to try to discover his accomplices. 

"We believe this suspect is only a courier, so there must be a drug dealing gang behind him," said Feng.

"Smugglers are adding extra troubles to customs officers by using sports shoes, as many people wear them when they are travelling," said Feng.  

In 2012, Beijing Customs impounded 26 kilograms of smuggled drugs, half the number of drugs that law enforcers discovered in the capital. 

"This number is almost the same as 2011. The major zones for drug imports are from Southeast Asia, Africa and South America," said Feng.

According to Chinese law, those who smuggle, traffic, transport or manufacture heroin or methamphetamine over 50 grams can be punished by 15 years' jail, life imprisonment or be sentenced to death.

Briton Akmal Shaikh was executed in 2009 after he brought 4,030 grams of heroin into China in 2007, although he claimed he did not know he had the drugs in his luggage.

Statistics from Beijing Municipal Public Security Bureau's website show police investigated 1,400 drug cases and arrested about 1,400 suspects, with 3,800 drug users detected and more than 50 kilograms of drugs impounded in 2012.