Todd's parents say his work had involved the use of an advanced semiconductor material Gallium Nitride, which has both commercial and military applications.

They say he had expressed concerns about the legality of his work and whether it could be harmful to U.S. security.

Singapore denies there were any illegal transfers of technology between IME and Huawei.

In a statement from Singapore's Foreign Ministry, Singapore also objected to the "pressure" in this case and said the country has "made every effort to be open and transparent in both the investigation of Mr. Todd's death and the IME's projects."

"We will let the outcome of the investigation and coroner's inquiry speak for themselves."