An investigation has found that the physicist who claimed to have developed one of the first room-temperature superconductors engaged in “research misconduct,” as first reported by 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 University has completed a thorough investigation conducted by a panel of scientists external to the University who have expertise in the field,” University of Rochester spokesperson Sara Miller says in a statement to The Verge. “The committee concluded, in accordance with University policy and federal regulations, that Dias engaged in research misconduct.”

Last year, Dias co-authored a research paper in Nature highlighting a nitrogen-doped lutetium hydride. The paper claimed the material could conduct electricity at ambient temperatures without resistance. (If that sounds familiar that’s because you’re thinking of the supposed LK-99 superconductor that went viral on social media last year.) Scientists later found inconsistencies in Dias’ research.

This paper, along with some of Dias’ other work, has been retracted. The committee “identified data reliability concerns in those papers” Miller says. “The University of Rochester is committed to academic integrity.”

Before this recent probe, 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.

Update March 20th, 5:56PM ET: Added a statement from a University of Rochester spokesperson.

Correction March 20th, 5:35PM ET: A previous version of the article incorrectly stated Dias’ research pertained to LK-99 when it was a nitrogen-doped lutetium hydride. We regret the error.