Twenty-one people are in custody in connection with what investigators call a multimillion-dollar fraud trend in Miami-Dade, authorities announced.

"As your sheriff, I made a clear promise I would root out fraud and corruption wherever it hides," said Miami-Dade County Sheriff Rosie Cordero-Stutz.

MDSO's auto task force, working alongside the county's tax collector's office, made the arrests of people described as straw buyers who, investigators said, illegally purchased vehicles at multiple dealerships.

"A single straw can purchase as many as 20 vehicles over the course of a week before the purchases register on the credit report," Cordero-Stutz explained.

Fake paperwork used to purchase vehicles

According to investigators, suspects used phony documents to obtain the cars, including fake W-2 forms, false addresses and pay stubs.

"They can report themselves to be the owners of a company that they're truly not the owner of, give fake bank accounts, [and] provide fake utility receipts to prove their residency," said Det. Luis Paz of MDSO.

Once the cars were purchased, investigators said the suspects would remove liens, create fake vehicle identification numbers, then export or illegally sublease the vehicles.

"Too often those illegally subleased cars are used in shootings, robberies, and other violent crimes," Cordero-Stutz said.

100 vehicles fraudulently purchased

Authorities said 100 vehicles were fraudulently obtained, with a total value of $5.5 million. So far, 53 of the cars have been recovered.

"When financial institutions lose millions, those costs are passed down to families, to small businesses, to consumers in Miami-Dade County with higher prices and higher insurance premiums," Cordero-Stutz said.

Dealerships targeted in ongoing investigation

Investigators said some of the dealerships targeted in the scheme are large, family-owned businesses. Officials added they are working closely with dealerships and financial companies to prevent similar fraud in the future.

The investigation remains ongoing.