It has been a rough year for materials scientist Akihisa Inoue, the president of Tohoku University in Japan.

Last March, an earthquake crippled his campus (see Nature 483,141–143; 2012). Since then, he has had to retract a series of papers because they contained text that had appeared in his previous publications, and has faced continuing calls for his resignation from the university, which he has rejected. His critics, mostly professors at his university, claim that some of his work cannot be replicated, and that there are irregularities in the data in some of his papers (see Nature 470, 446–447; 2011).

Inoue denies any manipulation of data, and there is no evidence that he has committed any scientific misconduct. Indeed, with more than 2,500 publications to his name, Inoue is one of the world’s leading experts in metallic glasses, materials that are more elastic and more resistant to corrosion than metals. He has previously told Nature that other researchers may simply lack the skills and experience to reproduce some of his lab’s results.

Yet Inoue’s battle with his detractors is far from over. Since January, two inquiries into his research have reported their conclusions. One offered a rebuke for the duplications; the other recommended a further investigation, giving his critics renewed vigour. The row raises questions about how universities in Japan should investigate allegations against their most senior staff, given that the country has no external body with this responsibility.

In December 2007, a committee from Tohoku University dismissed the need for an official investigation into Inoue, on the basis that there was no case against him. But Inoue’s critics were not appeased, because, they argued, the majority of the committee had been appointed to their administrative posts (but not to the committee itself) by Inoue. The committee denied any conflict of interest, adding that it was able to judge the case fairly.

 Since then, materials scientist Fumio Saito at Tohoku has pointed out that the text in seven of Inoue’s papers substantially duplicated work previously published by Inoue’s lab. These seven papers have since been retracted. Inoue told Nature that the duplications were accidents, or the result of miscommunication with co-authors.

Under pressure to take a closer look at Inoue’s work, Tohoku’s directors assembled another committee in February 2011. On 24 January, that committee’s final report concluded that although Inoue was at fault for the duplications, and that it should not happen again, the reuse of text is, to some degree, accepted practice in materials science, particularly in papers that draw on conference proceedings.

The Japan Science and Technology Agency (JST), a government funding body that gave Inoue ¥2.1 billion (US$26 million at the current exchange rate) to support his research from 1997 to 2007, also launched an investigation. It commissioned Makoto Misono, head of the Japan Union of Chemical Science and Technology, to lead a committee to investigate whether the duplications and alleged data irregularities called any of Inoue’s main results into question. Its report, released on 17 February, concluded that they had not.

The committee did not investigate any other allegations, but suggested that to settle the matter once and for all, an independent body should conduct an inquiry. The university says it is already conducting the investigation requested by the JST, but has declined to provide any details about its remit. Inoue has declined to comment on Misono’s report, or on its call for an independent investigation.

The broader message of the affair, Misono says, is that Japan should give more responsibility for the oversight of research conduct to an independent body such as the Science Council of Japan, an advisory body to the government. In general, Misono says, “when evaluating claims of scientific misconduct, it is necessary to have objective and fair investigation. If a research institution cannot do that, it’s necessary to have an independent third party.”