A year and a half after Purdue University began an inquiry into a physics professor’s controversial research into fusion energy, and seven months after it exonerated him of misconduct, the university announced today that it was reopening the investigation.

The professor, Rusi P. Taleyarkhan, has been criticized for a 2002 paper in the journal Science that reported that his laboratory had created a form of “tabletop,” or inexpensive, nuclear fusion. But critics have said the experimental results were impossible to reproduce and have implied that they were spurious.

The exoneration drew the attention of the U.S. House of Representatives last spring because Mr. Taleyarkhan’s research was conducted with federal grant money. In May a House subcommittee issued a report criticizing Purdue’s inquiry as secretive and inadequate, and the panel’s chairman warned that a federal investigation might follow if the university did not take a fresh look at the controversy.

That seems to be thrust of today’s announcement, in which Purdue said an internal committee had determined that “several matters merit further investigation.” —Andrew Mytelka