Federal prosecutors announced the case closed on investment fraud schemes that took $23 million from 700 people across the country, targeting elderly and unsophisticated investors with pitches about backers like an ex-Apple Inc. CEO, they said.

U.S. District Judge Marcia G. Cooke in Miami sentenced Craig Sizer, 49, of Miami to 15 years in prison Wednesday after he pleaded guilty to conspiracy to commit wire and mail fraud, prosecutors announced.