Updated

DETROIT -- Baggage handlers working for Delta Air Lines Inc. conspired to smuggle drugs to Detroit from airports in Houston and Jamaica, authorities said Thursday as criminal complaints were unsealed against 12 people.

The handlers were paid to ensure that certain suitcases were steered away from international baggage belts and placed in carousels from domestic arriving flights, Homeland Security agent Kurt Fiegel said in a court filing.

The bags were marked with a red "X" or had plastic bags or plastic ties on the handle, he said.

Ten of the 12 people charged were former or current Delta baggage handlers, said Brian Moskowitz, head of investigations in Michigan for U.S. Immigration and Customs Enforcement.

At a news conference, Moskowitz said the smuggling appeared to have occurred over a "period of several years," but he declined to elaborate or indicate the total amount of drugs that entered the U.S. from Jamaica.

The investigation began in January 2010 at the airport in Montego Bay, Jamaica, when 53 pounds of marijuana was discovered in a suitcase bound for Detroit, Fiegel said.

When Northwest Airlines flight 2321 landed in Detroit, authorities seized five suitcases with 284 pounds of marijuana and 35 pounds of cocaine, the agent said. Delta is Northwest's parent company.

"A shipment of this size had almost no chance of successful entry to the United States" if it had gone through the typical inspection process, Fiegel said in an affidavit filed to support the drug charges.

Delta issued a statement saying the employees have been suspended without pay.

"Additional disciplinary action could be taken pending the final outcome of the investigation," the Atlanta-based company said.

The Houston leg of the investigation began in March 2010 when agents seized 45 pounds of marijuana at the Detroit airport.

The defendants made their initial court appearance Thursday in Detroit, Houston and southern California. Two people were arrested in Houston and one in California.

Moskowitz said the Delta employees abused their access to planes and restricted areas of the airports.

"There's no perfect system. It's a matter of managing risk," he said.