The alleged crimes of the Brooklyn man arrested Thursday for dealing in black-market kidneys were first reported by an anthropologist from the University of California, Berkeley, who learned of the man's suspected involvement through her research.

Nancy Scheper-Hughes - whose contacts in Israel define her as the world's leading authority on organ trading - says she heard reports that the suspect, 58-year-old Levy-Izhak Rosenbaum, held donors at gunpoint after they changed their minds about the operation.

Such reports that she received from her sources compelled her to go to the authorities. She met with an FBI agent at a Manhattan hotel and gave him information about Rosenbaum, but she says that the Bureau acted only much later. The Berkeley scholar is said to have identified Rosenbaum to the FBI seven years ago as a major figure in a global human organ ring.

The anthropologist says that the man who led her to Rosenbaum says that he initially believed Rosenbaum was a man who saved the lives of people in need. According to Scheper-Hughes, that man told her he had changed his mind after meeting some of Rosenbaum's donors - confused and impoverished people from Eastern Europe.

One out of every five adult males in some of Moldova's poorest villages has had his kidney removed, according to Scheper-Hughes. But a 2004 State Department report stated that "it would be impossible to conceal a clandestine organ trafficking ring."

Back in Brooklyn, Rosenbaum was contacted by an FBI informant - Solomon Dwek, the son of a well-respected rabbi - who introduced Rosenbaum to an undercover agent who said she wanted to buy a kidney for her uncle. During one encounter, Rosenbaum is said to have boasted that he had facilitated "many deals and had never failed." Rosenbaum was recorded saying: "I'm doing this a long time."