Nature has uncovered further instances of apparent plagiarism in papers co-authored by government ministers and senior officials in Iran. The spate of new examples raises questions about whether such incidents are symptomatic of conditions also common in other developing countries — such as difficulties with English or pressure to acquire academic credentials as a prerequisite for promotion — or whether they are also linked specifically to the Iranian regime, where growth of a merit-based university culture has been undermined by political appointments and purges of reform-minded scientists (see page 699).

Research papers co-authored by Hamid Behbahani contain text from other works. Credit: A. KENARE/AFP/GETTY

An earlier probe1, 2 revealed extensive plagiarism in a paper co-authored by transport minster Hamid Behbahani and four papers co-authored by science minister Kamran Daneshjou. The revelations received wide coverage in the Iranian media and blogosphere. Scientists inside and outside the country have called for investigations, as well as for stronger ethical oversight in Iran's research institutions.

Daneshjou, a mechanical engineer at the Iran University of Science & Technology (IUST) in Tehran, was head of the interior-ministry office that oversaw this year's disputed election that kept President Mahmoud Ahmadinejad in power. In October, the Iranian parliament's commission for science and education held an informal inquiry into the four Daneshjou papers. Although it made no official conclusion, it effectively cleared Daneshjou after his co-author, IUST colleague Majid Shahravi, took responsibility for the papers' contents in the Iranian media — although both Shahravi and some members of the commission also maintain that the papers contained originality. Three of the four papers have now been retracted by the journals in question — the fourth was in an Iranian journal.

The paper3 by Behbahani, an IUST researcher who supervised Ahmadinejad's PhD, has not been investigated, although it seems to be almost entirely put together from three earlier articles by different authors2. It was retracted by the journal Transport in October.

Behbahani has publicly said that the paper did not constitute plagiarism because only parts of the article were identical to earlier work. He challenged the allegations of plagiarism, calling them a "media attack, far from fairness and integrity" and "an illegitimate accusation".

Nature has now uncovered yet more instances of apparent plagiarism in papers from Behbahani and some of his co-authors.

One paper4 on asphalt-road resistance — by Behbahani's Transport co-authors Hassan Ziari, a deputy minister of roads and transportation whom Daneshjou recently appointed as head of Payame Noor University in Tehran, and Mohammed Khabiri, then a PhD student at the IUST — contains many sections that are identical to a 2005 paper5 by scientists in Pakistan.

And two 2008 papers6, 7 on strengthening asphalt roads, co-authored by Behbahani and Ziari with PhD student Shams Noubakhat, also contain duplicated material. The first6 includes multiple passages from three earlier papers8, 9, 10 and the second7 is also largely taken from three other papers10, 11, 12.

One scientist familiar with the field, who asked to remain anonymous, says that he has difficulty making sense of the first paper's results, and that some data in it6 are identical to those in one of the earlier papers by different researchers8. "That the two sets of results could be identical is improbable," he says. Behbahani and Ziari did not respond to requests for comment. Muhammad Atif Ramay, managing editor of the Journal of Applied Sciences Research in which both papers were published, says that the journal has withdrawn the articles from its website pending further investigation.

Also in question is a 2008 paper on modelling pollution in Iran13, which is co-authored by one of the 37 members of the Iranian Supreme Council of Cultural Revolution, Mohammad Ali Kaynejad, an environmental engineer at Sahand University of Technology in Tabriz, Iran. The paper almost entirely duplicates a 2001 conference paper14 on modelling pollution in Hungary.

The Iranian paper acknowledges the original source of the model, although the authors wrote that it was "tested via the simulation of a photochemical oxidant episode that took place in Tabriz, Iran in 2007". But Alison Tomlin, an environmental modeller at the University of Leeds, UK, and a co-author on the Hungary model, says that the Iranian paper contains "no new results" and "is definitely a copy". It includes computer simulations purportedly of Iranian data, but they match the Hungary figures — and the background map outlines Hungary, not Iran.

The first author of the Iranian paper, Esmaeil Fatehifar, an environmental engineer at Sahand University of Technology, places the responsibility on another member of the team. "He said these are measured data about Tabriz Petrochemical Complex," he says. "I thought he was right and accepted it." Fatehifar says he intends to cancel the team member's PhD plans. He adds that Kaynejad had "not seen that paper" even though his name is on it. Kaynejad did not respond to Nature 's interview requests.

Questions have also been raised over work co-authored by Ali Reza Ali-Ahmadi, education minister in the previous government of Ahmadinejad. A 2006 paper15 on supply networks co-authored by him includes many sentences and paragraphs that are identical to those in three earlier papers16, 17, 18. Mika Ojala at Tampere University of Technology in Finland, a co-author on one of the earlier studies, says that in his opinion this is not coincidence. Ali-Ahmadi could not be reached for comment. Babak Amiri, an IUST researcher and a co-author on the paper, says that a draft version of the paper was accidentally submitted before it was checked by himself or Ali-Ahmadi. "I apologize for this big mistake," he says.

Nature has also learned that the US National Academy of Sciences earlier this year removed a chapter from a 2003 book19 on a US–Iranian workshop. Ironically, the chapter, authored by Hassan Zohoor, secretary of the Academy of Sciences of the Islamic Republic of Iran, was called 'The impact of moral values on the promotion of science'. It was withdrawn because it substantially duplicated a 1999 paper20 by Douglas Allchin, a historian and philosopher now at the University of Minnesota in Minneapolis.

Zohoor says that he never saw Allchin's paper, and that he only prepared a draft of the paper, leaving others in his office to "develop it and add the literature review". Zohoor says that the explanation of the staff member involved — that the copying happened "quite accidentally and as a mere negligence" — is inadequate, and that he intends to write to Allchin to apologize. "In my entire life I've never copied anyone else's work," says Zohoor.