Months before Shane Todd was found hanging in his Singapore apartment the American engineer told his parents his life was being threatened in a shadowy world of high tech secrets and espionage.

“We believe our son was murdered. We know our son was murdered,” says Mary Todd, a 57 year-old US pastor who has arrived in Singapore for a coronial inquiry that centres on claims about Huawei, the Chinese communications company likely to emerge with all or part of a $2 billion-plus contract to build an ultra-fast mobile network for Optus in Australia.

Disbelieveing: Rick and Mary Todd at the Subordinate Courts in Singapore. Credit:AP

According to Singapore's official version of events Shane Todd, 31, committed suicide in June last year, one week before he was due to return to the US after an 18-month stint working for a Singapore-government research centre known as the Institute of Microelectronics (IME).

But the death has struck a nerve amid global tensions over alleged spying operations originating from China after the chance finding of what Mrs Todd thought was a speaker among her son's belongings days after his death.