SIOUX FALLS - A man accused of running an online prostitution ring in southeastern South Dakota is on trial in federal court in Sioux Falls.

Prosecutors allege that Carl Campbell used violence and coercion to bring both minors and adults into the operation. Campbell's attorney says people involved in the ring were willing participants.

The Argus Leader reports that Campbell is charged with sex trafficking by force, fraud or coercion; sex trafficking of a child; interstate transport for sex trafficking; and obstruction of sex trafficking enforcement. He could spend the rest of his life in prison if convicted.

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