By Fayen Wong

SHANGHAI (Reuters) - Chinese police are investigating the death from unnatural causes of the deputy commissioner of customs at Qingdao port which is under investigation for alleged commodity financing fraud, state news agency Xinhua said on Thursday.

Xinhua said Qingdao Customs Deputy Commissioner Bian Peiquan died on Aug. 5. It did not give any further details.

Officials at Qingdao Customs did not respond to telephone and fax requests seeking more details. Qingdao police declined to comment, adding that investigations are ongoing.

The major fraud investigation at Qingdao port has prompted global banks and trading houses to fire off a series of lawsuits over their estimated $900 million exposure.

It was not clear if Bian's death has any links to the port scandal, but his death comes after a number of high-profile suspected suicides of executives from large state-owned firms since President Xi Jinping launched a campaign against graft last year.

Bian, 59, was in charge of the operations at the service center and staff training, according to the official customs website.

A source that knows Bian directly said his administrative role in customs would give him limited exposure to the port's business activities.

The customs authority is in charge of eight terminals located in the northern Shandong province, including Qingdao, Rizhao, Weihai and Yantai ports.

Global banks including HSBC and Standard Chartered have launched legal action since Chinese authorities started a probe into whether the firm at the center of the allegations, Decheng Mining, used fake warehouse receipts to obtain multiple loans at Qingdao port. Decheng Mining has not commented on the case.

(Reporting by Fayen Wong and Polly Yam; Editing by Paul Tait, Ed Davies and Michael Perry)