He offered each of the expecting mothers $10,000 to put their newborns up for adoption, siphoning off money for housing and health care after arranging for them to travel more than 5,000 miles from the Marshall Islands to the United States, prosecutors said.

Then, after falsifying their residency records to enroll them in state health care coverage, Paul D. Petersen commanded a $35,000 fee from parents eager to adopt, according to the authorities.

That’s how the alleged adoption fraud scheme operated for three and a half years, until Mr. Petersen, the elected assessor of Maricopa County, Arizona, and a private adoption lawyer, was indicted this week in three states.

Mr. Petersen, 44, of Mesa, Ariz., is accused of placing at least 29 babies from the South Pacific island nation with adoptive families and bilking taxpayers of $814,000 in health care costs, according to a 32-count indictment in Arizona. The felony charges against him include fraud, forgery and theft.