The body of 31-year-old electronics researcher Shane Todd was discovered by his girlfriend in his flat in June 2012, sparking a controversy that reached the highest levels of the Singapore and US governments after his parents refused to accept suicide findings by the Singapore police.
Todd's family say that he was murdered as part of a conspiracy involving a Chinese technology firm.
After two weeks of public hearings in May, the Singapore government rejected the murder theory and said Todd killed himself after a bout of depression.
But the Todd family remains insistent that he was murdered because of his work at his former employer, Singapore's state-linked Institute of Microelectronics (IME).
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They claim that he was involved in a secret project for Huawei Technologies, a Chinese telecom giant seen by Washington as a security threat.
IME and Huawei said they only held preliminary talks on a potential project with commercial applications, but did not proceed.
She told AFP the family was planning to set up a website called "Justice 4 Shane" to press their case and offer evidence to the public, including photographs of her son's body.
The family attended the Singapore inquest in May but angrily walked out after six days and flew home, saying they had "lost faith" in the proceedings.
During the hearings, their star witness, US pathologist Edward Adelstein, recanted an earlier theory that Todd was garroted with a cord in his own apartment.