Singapore and US investigators have begun sharing information on the controversial death of an American scientist found hanged in the city-state last year, the Singapore police confirmed on Friday.
The case involves Shane Todd, whose parents believe he was murdered in connection with his work for a Singapore institute with alleged links to a Chinese firm suspected of espionage activities by Washington.
Singapore police investigators reported Todd's death as a suicide but US officials are pressing for a deeper investigation.
The Singapore Police Force (SPF) and the US Embassy in Singapore issued separate statements on Thursday saying their law enforcement officials met in Singapore on March 18 to discuss the Todd case.
A police spokesman confirmed on Friday that the SPF and the US Federal Bureau of Investigation had begun sharing information on the case.
In its statement, the US Embassy said "productive, forthright" discussions took place but declined to give further details.
"This case is ongoing and led by Singapore law enforcement authorities. For that reason we will not comment on the details of our discussions or speculate on the outcome of the investigation."
Under Singapore law, the cause of death is to be officially declared by a coroner's inquest. No date has been set for the process.
Todd, a researcher at Singapore's state-linked Institute of Microelectronics (IME), was found hanged in his flat in June 2012. He was 31.
Todd's family claims he may have been murdered because he was working on a project involving China's Huawei Technologies.
A US congressional committee last year labelled Huawei and ZTE, another Chinese telecom firm, as potential national security threats that should be barred from government contracts and from acquiring US firms.
IME and Huawei have said that talks on a joint collaboration did not progress beyond preliminary stages.
IME has also said that the institute and Todd were never involved in any secret research project and welcomed a US audit of its internal processes.
The discussions between the two countries' law enforcers followed a visit to Washington last week by Singapore Foreign Minister K. Shanmugam during which he met with his counterpart John Kerry and Attorney General Eric Holder.
Shanmugam also held talks with Senator Max Baucus, from the Todd family's home state of Montana, who has called for US involvement in the investigation.
The Financial Times reported in February that Todd was working on a project using gallium nitride (GaN), a semiconductor material with military and commercial applications.