SIOUX FALLS, S.D. (AP) — The top federal prosecutors from South Dakota and North Dakota say they're increasing their focus on health care fraud cases.

U.S. Attorney Brendan Johnson of South Dakota tells the Sioux Falls Argus Leader that he has restructured his office to allow lawyers in the criminal and civil divisions to devote "significant time" to investigating fraud.

Johnson's office recently settled an alleged fraud case involving two doctors at Sanford Health in Sioux Falls.

U.S. Attorney Timothy Purdon of North Dakota says his office has added a special prosecutor who works specifically on cases involving doctors and others who work with Fargo-based Noridian Healthcare Solutions. Noridian handles Medicare claims from many states.

Purdon's office recently prosecuted a case involving a Seattle doctor accused of turning in phony Medicare claims.

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