A senior academic currently suspended by the University of Liverpool is carrying out his own investigation into alleged data duplication and plagiarism in several of his 70 published papers.
Alirio Melendez was suspended from his position as chair of immunopharmacology at Liverpool in April following allegations that data in several papers on which he was an author were manipulated or copied from other work.
The subsequent investigation, in which two of Professor Melendez's previous institutions, the University of Glasgow and the National University of Singapore participated, led to the retraction of a paper published in February in the journal Nature Immunology, on which Professor Melendez was the corresponding author.
The retraction notice, to which all the authors agreed, said irregularities identified in the figures meant that the paper's conclusions were no longer adequately supported.
Earlier this month Science published an editorial expression of concern about a 2010 paper, on which Professor Melendez was also corresponding author, pending the conclusion of the institutions' ongoing investigation. Science bloggers have raised questions about several other papers on which Professor Melendez is a prominent author.
It has now emerged that a large number of the previous papers on which Professor Melendez is an author are under "thorough investigation" by the National University of Singapore, where Professor Melendez remained a visiting professor until earlier this year, after moving to Glasgow in early 2007.
Barry Halliwell, deputy president of research and technology at Singapore, said the investigation was being conducted "in the interest of thoroughness".
He said Professor Melendez had authored nearly 70 papers and Singapore was investigating all of those on which it was listed as an affiliation, plus related papers published before Professor Melendez joined the institution in 2001. Professor Halliwell said Singapore was "coordinating closely" with Liverpool and Glasgow and would conduct its investigation "as swiftly as possible, subject to thoroughness".
But Professor Melendez said he was also carrying out his own investigation. He admitted to Times Higher Education that "some of the data appear to have been duplicated/plagiarised or accommodated to fit a few papers". But he stood by his science and insisted that he had played no part in any misconduct.
"My mistake was to be too trusting," he said. "I realise I should have been more vigilant, but it is very difficult to know what is going on in a lab: more so when the principal investigator is in another continent."
The leaking of information from the investigation suggested there was a "campaign to smear my name", Professor Melendez said.
A statement by the University of Glasgow said that there was "no evidence that our current staff contributed falsified or duplicated data to any publications co-authored with (Professor) Melendez".
Last year, 12 papers by University of Manchester professor of immunobiology Silvia Bulfone-Paus were retracted after an investigation by the Research Centre Borstel in Germany, where she also holds a position, concluded that research misconduct had occurred in her lab.
The University of Lubeck is also investigating allegations of data duplication by her husband, Ralf Paus. But the University of Manchester, where he also holds a professorship in cutaneous medicine, decided against opening its own formal inquiry.