An expensive but widely panned promotional video made for China's Ministry of Railways has triggered a corruption investigation into a couple who are both ministry officials.

Graft probe sparked by costly film about trains.[ File photo ]

In June, the country's top auditor found that the ministry had spent 18.5 million yuan (US$2.9 million) on the five-minute video, "Chinese Railways," without going through a public bidding process.

That led to suspicion of violations or corruption, and authorities began an investigation into Chen Yihan, deputy general secretary of the ministry's literal and arts department, early this month.

An insider said inspectors seized more than 10 million yuan in cash and at least nine property ownership certificates from Chen's home.

Chen, a low-ranking official, couldn't have amassed such an amount of money and property, according to investigators. Then her husband, Liu Ruiyang, deputy director of the vehicle department, was brought into the investigation. Bank deposit books and shopping cards were found in Liu's office, Caixin.com reported yesterday.

"We didn't expect to get a somebody because we had planned to just catch a nobody," the insider was quoted as saying.

Another unnamed source told the news website that Liu was promoted in April and he had been responsible for vehicle purchases in his previous role.

Liu graduated from Dalian Jiaotong University in 1984 and became a section chief with the ministry and deputy head of the Beijing Railway Bureau. Chen used to work for the ministry's publicity department.

The video also put renowned Chinese film director Zhang Yimou at the center of a media storm because the ministry claimed he had directed it.

However, in a statement, Zhang's assistant said Zhang, who had been invited to take part, just offered advice in the project's early stages.

Zhang didn't know that the video would include a credit for "Zhang Yimou Works."

The video was played at the opening of the 7th World Congress on High-Speed Rail in Beijing in December 2010 as well as in high-speed trains.

It showed China's railway development by simply showing running trains. Internet users called it boring and wondered how so much could have been spent on such a poor video.