The Select Committee tasked to study fake news said it did not find historian Thum Ping Tjin to be credible and gave no weight to his views.
It gave three reasons in its report yesterday: Dr Thum lied about his academic credentials, admitted that his research on historical events surrounding the 1963 Operation Coldstore was flawed, and failed to follow up with documents he said he would send to the committee after the hearings.
When the committee sought public views early this year on deliberate online falsehoods, he had written in, saying fake news had not had much of an impact in Singapore, save for one major exception: Operation Coldstore, when over 100 leftist politicians and unionists were arrested and detained. He added that the People's Action Party had used fake news in that operation to detain political opponents.
In an addendum to its report, the committee said Dr Thum had referred to himself as a research fellow in history at Oxford University.
When he was questioned at the public hearings, he said he had switched to anthropology, and held a visiting professorship in anthropology at the university.
The Parliament Secretariat also found that he had described himself online as a visiting research fellow in history in the department of anthropology.
Dr Thum, however, never was a research fellow in history at Oxford, said the committee.
It also said Oxford confirmed he was never an employee of the university, but was a visiting fellow with the Fertility and Reproduction Studies Group in the School of Anthropology.
Before that, he was a visiting scholar, not a research fellow, at the Oxford Centre for Global History, another unpaid position, it added.
In his visiting scholar arrangements, he had certain privileges in return for a fee paid to Oxford.
"Those visiting arrangements are different from the picture Dr Thum sought to paint with his claims to be a 'research fellow in history' and the holder of a 'visiting professorship' - a picture that he held an academic position of some seniority with Oxford University," it said.
The committee also noted that when presented with statements by historical figures like Communist Party of Malaya chief Chin Peng, he acknowledged that they contradicted his research paper's position that there was no evidence of communist involvement in the progressive left in Singapore in the 1960s.
He also admitted that he disregarded the writings of some senior cadres of the Communist Party.
And when presented with declassified British documents that he had examined for a paper he had cited in his written submission, he admitted that his presentation of these documents was misleading.
Speaking at a media briefing on the committee's report yesterday, Select Committee member K. Shanmugam, who is Law and Home Affairs Minister, said: "Since his perspective was unique, we thought we would set out what we thought of his representation."
The committee also outlined events that happened after the hearings. In April, an open letter to committee chairman Charles Chong was circulated online, with signatures from academics from different countries.
It expressed "deep concern" at the committee's questioning of Dr Thum, and its wider implications for freedom of expression and academic freedom in Singapore.
Later that month, the trustees of Project South-east Asia stated their support for Dr Thum, one of the project's trustees.
The addendum said both the open letter and trustees' statement "cast aspersions on the committee's process (and) were based on wrong facts and premises".
It added that at the hearing, Dr Thum agreed to come back to the committee with two documents: Special Branch records he relied on for his research paper and a publication in which he had indirectly critiqued a statement by Chin Peng.
He submitted only the former.
The addendum also said Human Rights Watch (HRW) and Reporters Without Borders were invited to the hearings, but they declined.
Mr Shanmugam said the committee thought their excuses for not turning up were "contrived".
Both had initially accepted the invitation, but HRW later said its representative had made travel plans that "could not be changed", and Reporters Without Borders cited "organisational reasons".
The committee offered both groups the option of a video conference call, but neither took it up.