An investigation has found that the physicist who claimed to have developed the world’s first room-temperature superconductor engaged in “research misconduct,” according to a report from The Wall Street Journal. Ranga Dias, a researcher and assistant professor at the University of Rochester, has been under investigation by a committee of outside experts since last August over concerns about the accuracy of his findings.

“The committee concluded, in accordance with University policy and federal regulations, that Dias engaged in research misconduct,” a spokesperson for the University of Rochester tells the Journal.

Last year, Dias published a research paper in Nature highlighting a material called LK-99. It claimed that the material could conduct electricity at ambient temperatures without resistance. The supposed superconductor went viral on social media as some touted it as a major physics breakthrough. However, the hype quickly wore off as scientists found inconsistencies in Dias’ research that suggested LK-99 is not a superconductor.

This paper, along with some of Dias’ other work, has been retracted. The committee “identified data reliability concerns in those papers,” a spokesperson for the University of Rochester tells the Journal. The university didn’t immediately respond to The Verge’s request for comment.

Before the LK-99 investigation, the university opened two inquiries into Dias’ research, but it decided against opening a full investigation. As noted by the Journal, the university could also decide to take personnel action against Dias as a next step, which is handled by the institution’s provost.