St. Lawrence County Dist. Atty. Mary E. Rain told the Los Angeles Times that Stephen Howell II, 39, and Nicole Vaisey, 25, were charged with first-degree kidnapping in the disappearance of Fannie Miller, 12, and Delia Miller, 6, in upstate New York on Wednesday night.
Howell and Vaisey voluntarily met with police for an interview Friday and were subsequently arrested, Rain said. She declined to say why the couple agreed to meet with police or what authorities suspected as a motive.
Rain said further details would be offered at a news conference Saturday.
Neither suspect had any previous arrests, according to Rain, who said Howell worked as a nurse at a local hospital. The couple live in Hermon, N.Y., a town not far from Richville, where the girls were released unharmed Thursday night.
The search had been complicated by the Amish avoidance of modern technology. Photos of the girls were not available when an Amber Alert was issued after their disappearance.
Rain said the girls pointed police in the direction of the suspects.
"They're absolutely relieved," Rain said of the family. "The children were very strong during their interviews with police, but that is the Amish way."
The girls disappeared Wednesday night after a white car pulled up to their family's vegetable stand in Heuvelton, N.Y., Rain said. The girls believed the driver was a customer, she said.
Rain said Howell and Vaisey took the girls "against their will" but declined to elaborate.
Witnesses previously told police they saw one suspect, a man, shove something into the back seat of a white four-door sedan before the vehicle drove off.