Federal authorities say an investigation into the theft this summer of several semitrailers loaded with frozen beef from Nebraska has led to arrests and uncovered a multimillion-dollar theft ring targeting meatpacking plants in six Midwestern states. The U.S. Department of Homeland Security reported Tuesday that the discovery of the Miami-based theft ring began in June when several semitrailers loaded with nearly $1 million in frozen beef were stolen near the Nebraska cities of Lincoln and Grand Island. An investigation determined that beef and pork packaging plants in Nebraska, Iowa, Minnesota, South Dakota, North Dakota and Wisconsin were being targeted. On Oct. 20, investigators arrested three Miami men on suspicion of transporting stolen goods and money laundering.