Sixty-one suspects stood trial in Beijing on Thursday, the sixth day in what the No 1 Intermediate People's Court said was the largest-ever case of contract fraud since the founding of the People's Republic of China in 1949.

The 61 suspects siphoned off more than 80 million yuan ($12 million) from 259 people between 2013 and 2014, according to the indictment provided by the First Branch of the Beijing Municipal People's Procuratorate.

They were alleged to have worked for a private internet service provider named Zhongwanghuying Internet Co, but they told their clients the company was run by the Ministry of Industry and Information Technology.

Some of them acted as the company's salespeople, soliciting clients through an online platform and persuading them to buy and register certain keywords said to have great market value, according to the prosecutors.

The clients later found that the registration, as well as the market value, were a sham; but other suspects continued to swindle the clients, prosecutors said. They approached those who had registered certain keywords and offered internet services, pretending that the keywords were sought after by well-known companies.

After being told that the keywords would command a higher price after an internet promotion, the clients paid the company a fee hoping to add market value to their websites. Only later did they discover that the business deals were based on lies, according to prosecutors.

In addition, they said, some of the company's staff hid their employment status and faked their identities, claiming that they were from well-known companies that intended to buy the keywords.

Tao Wei, who is in charge of a criminal court under the Beijing No 1 Intermediate People's Court, said more than 250 volumes of documents, each typically 1-3 centimeters thick, were collected for the trial.

The court said a verdict will be announced later.