The scientist at M.D. Anderson Cancer Center in Houston was hardly discreet. “Here is the bones and meet of what you want,” he wrote in a misspelled email to researchers in China.

Attached was a confidential research proposal, according to administrators at the center. The scientist had access to the document only because he had been asked to review it for the National Institutes of Health — and the center had examined his email because federal officials had asked them to investigate him.

The N.I.H. and the F.B.I. have begun a vast effort to root out scientists who they say are stealing biomedical research for other countries from institutions across the United States. Almost all of the incidents they uncovered and that are under investigation involve scientists of Chinese descent, including naturalized American citizens, allegedly stealing for China.

S eventy-one institutions, including many of the most prestigious medical schools in the United States, are now investigating 180 individual cases involving potential theft of intellectual property. The cases began after t he N.I.H., prompted by information provided by the F.B.I., sent 18,000 letters last year urging administrators who oversee government grants to be vigilant .