An American scientist found hanged in Singapore last year was murdered and his death made to look like a suicide as part of a conspiracy, a US pathologist told an inquiry Tuesday.
Edward Adelstein, 75, a deputy medical examiner in Missouri, contradicted Singapore police findings that Shane Todd killed himself, but admitted his conclusions were based on pictures of the body and second-hand information.
Todd's parents, who also plan to testify, say their son was killed in June 2012 because of his work for a Singapore electronics research institute with alleged links to a Chinese firm accused of involvement in espionage.
"The cause of death of Dr. Todd was strangulation by a ligature around his neck," Adelstein said in a written statement admitted as evidence Tuesday at the Singapore inquiry, adding that "I would rule his death a murder -- a homicide."
He said Todd was "a very dangerous person" to the two Asian companies, and asserted without offering any evidence that "they had him killed" and well-trained "assassins" may have been involved.
Adelstein was brought in to work on the case by the Todd family. Two other US medical examiners acting as independent experts support the suicide findings and will be asked to testify at the two-week inquest, Singapore officials say.
A verdict is expected by late June and will only address the cause of death.
Under questioning during a live video link from the United States, Adelstein said Todd could have been disabled with a taser -- an electronic device designed to stun -- and killed with an arm lock before being hanged.
In an October 2012 report, Adelstein had said that Todd, a well-built 31-year-old, was killed by "garroting" but on Tuesday the doctor said he was speculating at the time.
Todd's former employer, the Institute of Microelectronics (IME), and China's Huawei Technologies have denied working on a project involving Todd but confirmed they held preliminary talks on a potential research venture.
A US congressional committee last year labelled Huawei and ZTE, another Chinese telecom firm, as potential security threats that should be excluded from US government contracts and barred from acquiring US firms.
Todd was part of an IME research team working on gallium nitride, a semiconductor that can be used in radar and satellite communications.
Adelstein said photographs of Todd's remains at his US funeral showed knuckle injuries and a forehead bruise that could have resulted from a fight.
The US medical examiner, who said he had examined 40 people who died by hanging, questioned the competence of the Singapore police, saying their findings cannot be trusted.
Police investigators earlier testified that there were no signs of a struggle in the apartment where Todd's body was found hanging from the top of a locked bathroom door by his girlfriend.
A Singaporean psychiatrist told the inquiry that Todd was prescribed anti-depressants three months before his death in June 2012.
"I don't take psychiatric diagnosis very seriously," Adelstein said in his video testimony Tuesday. "It is not a real science. I am very suspicious of psychiatric diagnosis."
The doctor, echoing the family's statements, said Todd "was involved in research with a company that he felt was violating American security" and had "no unsolvable problems" that would have forced him to take his own life.
Former colleagues of the researcher have rejected the Todd family's claim that he worked on a secret project that could harm US security.
Todd's parents said in media interviews that he expressed fears for his life before resigning from the state-linked Singapore institute and had been looking forward to returning to the United States.