Singapore, RoS - It has been a death that continues to arouse suspicion nine months later, besides spawning tensions across oceans between the United States and Singapore.
Authorities in Singapore orginally said Shane Todd - a 31-year-old engineer from the US found hanging in June 2012 - had committed suicide. But speculation that the nature of his death could have been far more sinister has continued to swirl amid talk of top-secret research, potential threats to US national security, and shadowy links between giant technology firms and the Chinese military.
At the centre of the enduring mystery has been Todd's tryst with gallium nitride, a seemingly innocuous hard crystal compound with remarkable properties that can withstand extremely high temperatures. Its semiconducting abilities allow it to emit brilliant bright light - making it probably the most important semiconductor material since silicon.
But its importance really lies in its scientific potential to build powerful high-frequency transistors, making it a key material in military and science experiments.
"The FBI continues to follow the case closely, but it does not have jurisdiction outside the United States, and must be invited by a foreign government before doing any investigations overseas."
- Eric Watnik, US Embassy spokesman
Todd had reportedly uncovered top-secret information about gallium nitride while working with then-employer the Institute of Microelectronics (IME), a Singapore government science body that conducts specialised research. The research body was also alleged to have started a gallium nitride project with Chinese technology giant Huawei, one of the world's largest telecommunications providers.
Todd was reportedly "stressed" and "fearing for his life" after he made his supposed discovery. Todd's family have said he worried a project he was working on with an unnamed Chinese company may have been endangering US national security. He decided to leave IME, and was offered a well-paid job with a US research firm. Days later, in June 2012, his girlfriend entered his colonial-era home in Singapore's Chinatown district, and found his body hanging from a bathroom door.
"Gallium nitride is used in active array radars, a new type of radar that requires powerful receivers and transmitters," a senior scientist told Al Jazeera, requesting anonymity because of the story's sensitivity.
"As far as I can tell, the motivations [for military applications] lie in a military being interested in having more robust and faster electronics, and higher communication loads by wireless means," he said.
|IME denied running a project on gallium nitride amps
with Huawei [Heather Tan/Al Jazeera]
The IME has denied that either it or Huawei was involved in any such classified research project.
"The Institute did not go beyond preliminary talks with Huawei on a commercial project relating to gallium nitride power amplifiers for base station applications," read a statement. "The Institute does not have, and has never had, a project with Huawei on gallium nitride power amplifiers."
The institute acknowledged that it prepared a technical proposal for a project in September 2011, but stated no contract on gallium nitride power amplifiers was in place between IME and Huawei.
Huawei has also denied working with IME on a gallium nitride project.
In October, US lawmakers and military intelligence officials stated Huawei and ZTE posed a potential threat to national defence systems. A year-long US congressional investigation found the two Chinese firms may be spying on Americans. Both Huawei's links with the People's Liberation Army and concerns that it was helping China gather information on foreign states and companies have placed US officials on high alert.
Death in Singapore
An autopsy report filed by the Singapore Police Force labelled Todd's death a suicide, but suspicions - and murder allegations - arose after a visit from Todd's family. Initial investigations by the police claimed that bolts were built into the apartment's ceramic walls, and ropes and pulleys slung around the bathroom and over a door, setting the scene for an attempted suicide. But Todd's mother, Mary, a nurse, found no signs of the alleged evidence when she visited the apartment shortly after her son's death.
Instead, she told a news organisation in February that she discovered bruises on Todd's body and hands, and a lump on his head that could indicate signs of a struggle that may have caused his death. Also shocking was a suspiciously written suicide letter that contained incorrect memories, further leading the Todd family to believe he was murdered.
Todd's parents also discovered an external hard drive belonging to their son, which reportedly contained documents about the proposal between IME and Huawei to build a powerful amplifier using gallium nitride. The hard drive had been accessed shortly after his death. The Singapore police said they had opened it to uncover evidence.
"Based on what was reported so far, it seems that the account given by the police and that of Shane's parents do not corroborate."
- Kumaran Pillai, political commentator
Kumaran Pillai, a political commentator in Singapore who has been following the case closely, said it is hard to ascertain whether Todd's death was a cover-up.
"But based on what was reported, the circumstances surrounding the case are rather bizarre," Pillai said. "It seems that the account given by the police and that of Shane's parents do not corroborate."
In the wake of the Todd family's revelations, Singapore police reopened the case and invited US officials to take a greater look at the relationship between IME and Huawei.
Eric Watnik, a spokesman from the US embassy in Singapore, told Al Jazeera while the Singapore authorities have requested FBI assistance for the investigation, it continues to be led by Singaporean police.
"The FBI continues to follow the case closely, but it does not have jurisdiction outside the United States and must be invited by a foreign government before doing any investigations overseas," Watnik said.
On a visit to Washington, Singapore's Foreign Affairs Minister K Shanmugam met with Senator Max Baucus, who represents Todd's home state of Montana. Baucus has been pressing for more US involvement with the investigation, and stressed action must be taken to determine no suspicious activity occurred that might jeopardise US national security.
While Baucus reiterated he would "stop at nothing" to satisfy Todd's parents, Shanmugam stated that Singapore authorities "remain committed to getting to the bottom" of Todd's death. "We are the kind of country where this is done in public, with a public inquiry," said Shanmugam.
Baucus and Jon Tester, also a senator from Montana, have moved to block US funding to IME - an act that suggests scepticism and growing frustration at the speed and perceived lack of transparency surrounding Todd's case.
The senators had requested the FBI be given "full access" to all evidence in the investigation conducted by the Singapore authorities, based on "the version of the facts provided by the family alone".
Singapore's foreign affairs ministry said it was "deeply disappointed" by the plan to cut funding. "The issue of applying 'pressure' should not arise between countries which have had a long, open and cooperative relationship with each other, based on mutual respect," read a statement.
"Singapore has made every effort to be open and transparent in both the investigation of Mr Todd's death and the IME's projects," said the ministry.
"We will let the outcome of the investigation and coroner's inquiry speak for themselves."
The coroner's inquiry into Todd's death will start on May 13, state media reported Tuesday. The investigation continues as the mystery of his death deepens.
Follow Heather Tan on Twiter: @tanheather