Three Nigerian men were sentenced to prison time and restitution last week for their involvement in schemes that have targeted thousands of Pennsylvanians from York County and elsewhere, U.S. Attorney Peter J. Smith said Tuesday.

The three men - Christian Nwosu, 41, Alexander Ojiri, 53, and Kennedy Onaiwu, 42 - were charged with mail and wire fraud as part of an investigation into telemarketing scams using MoneyGram and Western Union. All three later pleaded guilty, the U.S. Attorney's Office said.

Nwosu and Onaiwu acted as complicit MoneyGram and Western Union agents, and Ojiri served as a "middleman" between them and fraudulent telemarketers, according to the U.S. attorney's office.

Nwosu was sentenced to 46 months in prison and $1,520,886 in restitution, Ojiri was sentenced to 46 months in prison and $798,742 in restitution, and Onaiwu was sentenced to 41 months in prison and $453,221 in restitution.

The cases are part of an ongoing investigation that has resulted in charges for 28 individuals and turned up $13.5 million in reported losses, according to the U.S. attorney's office. The U.S. Postal Service is leading the investigation.

Anyone with more information about suspected mass-marketing schemes is asked to call 1-877-876-4255 or file a complaint online at usps.com/postalinspectors or ftc.gov.