Eight members of the largest expatriate gang caught in Shanghai were tried this Monday and Tuesday at Shanghai No. 1 Intermediate People's Court.

The 25 suspects, all from South America, are charged with being involved in three thefts this May, in which a total of 6.13 million yuan (US$730,400) was stolen. The biggest theft involved stealing diamonds of more than 2,000 carats from an international jewellery exhibition.

Some of the other 17 members of the gang have already been tried, with a hearing to be arranged soon for the remainder.

"As the other two groups include underage suspects, the trials are not open to the public," said an official from the court who wished to remain anonymous.

On May 13, the gang visited a booth at the Shanghai Mart where the Fifth Shanghai International Jewellery Exhibition was being held.

While one of the suspects was trying to attract the attention of Guo Junxia, an employee of the Shanghai Jinghua Jewellery Co Ltd, by pretending to be interested in the diamonds, another one took away a canvas bag under the desk containing the diamonds, a mobile phone, and around 47,000 yuan (US$5,680) and HK$200 (US$26) in cash.

"The fact that this incident took place at an international fair has raised concerns among foreigners about the city's public security situation," said the prosecutor.

Following the theft, the police immediately set up a special squad and began to collect information from various sources.

Another theft involving expatriate criminals was reported several days later.

"On the morning of May 17, some members of the gang again conducted a robbery in the waiting hall of Pudong International Airport," said the prosecutor.

"While five of them were looking around, a suspect purposefully splashed some yogurt on an Indian jeweller, Vivek Agarwal, and another one took away his suitcase containing 46,506 carats of gems when the victim was cleaning his clothes."

The gems are worth nearly 1.6 million yuan (US$193,200).

Later in that evening, two suspects from the gang were first caught, one in a restaurant in the downtown area and the other in a hotel close to the railway station.

"In a fax sent by the Hong Kong police, we found the clue -- a group of South American suspects who were attempting thefts at last year's Hong Kong Convention & Exhibition Center," said Kong Xianmin, deputy director of the Shanghai Public Security Bureau.

Shanghai police began to cast eyes on foreign suspects from Central and South America, and conducted thorough searches in hotels, bars, airports and other places that foreigners frequently visit.

"The 25 suspects were all captured in two days," said Kong.

Upon being questioned, some of them confessed another robbery on May 12 in a local bank.

With one acting as a lookout, one talking to security, the third one threw a coin near the victim, Gu Xiangchen. The forth one pretended to warn Gu about the coin, and the last one stole 80,000 yuan (US$9,660) in cash wrapped in a newspaper behind the victim, according to the prosecutor.

"These eight suspects entered Shanghai from Hong Kong and Malaysia between May 11 and 13, just before the jewellery fair," said the prosecutor.

"There is evidence that they hatched the diamond theft in Malaysia. And what they have conducted deserve imprisonment above eight years."