For years, Prof. Bruce Bagley was a go-to expert for journalists reporting on drug trafficking, money laundering and corruption in South America. In 2016, for instance, he was asked about two nephews of the Venezuelan president who had been charged with drug trafficking.

“The nephews are just the tip of the iceberg,” Professor Bagley, who teaches international studies at the University of Miami, told Univision. “Corruption is rampant in power circles in Venezuela.”

Now federal prosecutors have accused Professor Bagley, 73, of being more than an academic observer in the criminal world that he spent his career studying.

On Monday, federal prosecutors announced he had been arrested on money laundering charges for his involvement in a scheme to hide the origins of more than $2.5 million in proceeds from bribery and corruption in Venezuela. They said he kept about 10 percent of the money for himself as a commission.