Purdue University in West Lafayette, Indiana, has sent federal authorities a report of its investigation into the work of nuclear engineer Rusi Taleyarkhan, Nature has learned.

Taleyarkhan is known for his claims to be able to produce fusion by collapsing bubbles in deuterated acetone by bombarding them with sound waves. His work had been subject to allegations of research misconduct, which Purdue had been investigating.

Taleyarkhan's lawyer, John Lewis of Lewis and Wilkins in Indianapolis, says that the final decision now lies with the inspector-general of the Office of Naval Research in Arlington, Virginia. The office funded some of Taleyarkhan's research through grants. The Purdue report is confidential, but Taleyarkhan plans to contact the office to challenge the report's “accuracy, adequacy and completeness”, says Lewis.

The engineer is also pursuing a defamation lawsuit, filed last month in Tippecanoe County in Indiana against scientists who questioned his claims of bubble fusion. The defendants include Purdue faculty members named in Nature articles, which helped trigger an institutional review. “The complaint filed is to clear up my reputation,” Taleyarkhan says.