China hopes to further intensify cooperation with US law-enforcement agencies to bring back three fugitives accused of corruption at home and exposed in a visa fraud probe in California, an official familiar with the matter said on Monday.

The two countries will try to keep in close contact and share information on the case, said the official who did not wish to be named due to the sensitive nature of the case.

The three people gained their US "green cards" by faking documents, and as a result those green cards could be revoked. "We'll enhance cooperation with our US counterparts and ask for assistance in arresting and bringing them back to China."

On April 5, US federal agents raided several locations in the greater Los Angeles area. They searched the office of the California Investment Immigration Fund, or the CIIF, in San Gabriel; a home in Arcadia; a town house in El Monte and a Porsche SUV. They seized computers, financial documents and other records for evidence of the suspected fraud.

No arrests were made, and Thom Mrozek, spokesman for the US Attorney's Office for the Central District of California, said on April 6 no charges had been filed against the suspects at this point. They could face charges of visa fraud, money laundering and conspiracy to defraud the federal government.

Victoria Chan, an attorney, and Tat Chan, her foreign national father, persuaded more than 100 Chinese nationals to invest a total of $50 million with the CIIF and related companies since establishing the business in 2008, according to a search warrant unsealed by the US District Court for the Central District of California.

The court document also named another suspect, Fang Zeng, the father's female companion and a Chinese national.

Among Chan's clients were at least three fugitives on China's 100 most wanted list, who were charged with crimes like bribery, according to the affidavit. They were able to obtain green cards based on false information.

Xu Jin, number 13 on the list, was formerly the director of the Wuhan Municipal Development and Reform Commission in Hubei province. He was suspected of abusing power and bribery. Xu used fake documents to obtain a temporary US green card in 2010 and fled China in 2011 with his wife, according to the Chinese government.

His wife, Liu Fang, number 66 on the list, was formerly deputy director of the Hubei branch of China Life Insurance Co. She was accused of bribery and obtained her US green card through deceit in 2010, according to the Chinese government.

There was little information about the third fugitive, identified as "K.L.", according to the affidavit.

The US has become a popular destination for corrupt Chinese officials to flee due to the lack of an extradition treaty and judicial differences between China and the US.