BEIJING- China's customs authorities are  investigating smuggling crimes committed by Lai Changxing, who was once one of China's most wanted fugitives, a senior customs official said on Thursday.

The case will be turned over to prosecutors when the investigation concludes, deputy director of the General Administration of Customs (GAC) Lu Peijun told reporters at a conference.

Lai was repatriated to China on July 22, 12 years after fleeing to Canada.

The 53-year-old alleged smuggling kingpin is the chief suspect in a multibillion-dollar smuggling operation that dates back to the 1990s in Southeast China's city of Xiamen.