SINGAPORE, May 22 (Reuters) - The parents of a U.S. engineer found dead in Singapore last year said on Wednesday they will not take part in the rest of a coroner's inquiry into his death, which they say was linked to a project involving the transfer of sensitive technology to China.
In a statement issued through their lawyers, Rick and Mary Todd said they had lost confidence in the system investigating the death of their 31-year-old son, Shane, who was found hanging in his Singapore apartment last June.
The Todds did not appear in court on Wednesday, the day after a U.S. medical examiner they had hired retracted an earlier statement that Shane Todd had been garrotted.
They walked out of the hearing later on Tuesday after the presiding coroner refused their request to delay testimony by a witness so that they could go through it.
"We no longer have confidence in the transparency and the fairness of the system. It appears to us that the outcome has been pre-determined," the Todds said in the statement read out by their lawyer, Gloria James-Civetta.
Singapore police have said Todd probably committed suicide.
His parents believe he was murdered, possibly because of what they said was his involvement in a project between Singapore's Institute of Microelectronics (IME) and Chinese telecommunications giant Huawei. Todd had previously worked for the institute.
His death has become a political issue, with U.S. Senator Max Baucus, who represents Todd's home state of Montana, pressing for more American involvement in the investigation.
Under Singapore law, a coroner's inquiry is needed for deaths that are not a result of illness. The state will present evidence and family members are allowed to question witnesses either directly or through their lawyers.
During the inquiry, which began on May 13, Singapore government lawyers presented forensic reports that showed Shane Todd had died by hanging based on injuries around his neck.
Their findings were backed by two U.S. pathologists, who said the manner of death pointed to suicide.
U.S. medical examiners, besides reporting on the injury, are also required to provide an opinion about the cause of death.
Edward Adelstein, the U.S. medical examiner hired by the Todds, said during cross-examination on Tuesday he had based his earlier finding of garrotting based on photographs provided by the Todds.
Testifying via Skype, Adelstein said he had not physically examined the body.
He also said on Tuesday he had changed his mind about the cause of death after reviewing evidence provided by Singapore authorities that showed no signs of broken blood vessels in the neck, consistent with strangulation by wire or cord.
However, Adelstein insisted that Todd was probably dead before he was hanged from a door in his apartment after being "tasered" or strangled in a "carotid armlock". He also said he could not show any evidence to support that.
The Todds' belief their son was murdered stemmed from documents on a hard disk drive they said they found in his apartment. He had been researching an advanced semiconductor material called Gallium Nitride (GaN).
Both Todd's former employer IME and Huawei said they did not proceed beyond initial discussions into a possible project involving GaN, which can be used in equipment ranging from mobile phone base stations to military radars.
Huawei has been blocked from some projects in Australia and is deemed a security risk by the U.S. Congress on the grounds that its equipment could be used for spying.