(CNN) -- Federal agents arrested 10 current or former Delta employees Thursday for their alleged involvement in drug trafficking at airports in Detroit and Houston, authorities said.
Two others who were not airline employees also were arrested.
"Today's arrests and charges close a major vulnerability at the airport," Immigration and Customs Enforcement director John Morton said in a statement. "We can't have people working in and around aircraft exploiting their positions for criminal ends."
The investigation -- dubbed "Operation Excess Baggage" -- began in January 2010, when Jamaican authorities seized 53 pounds of marijuana from a suitcase, the immigration and customs agency said in a statement.
The luggage, tagged with a Northwest Airlines baggage tag, was bound for Detroit Metropolitan Wayne County Airport from an airport in Montego Bay, Jamaica, the statement said. Delta and Northwest merged in 2008.
Authorities in Detroit later seized five suitcases containing 16 kilograms of cocaine and nearly 130 kilograms of marijuana, the statement said.
In March 2010, federal agents seized 45 more pounds of marijuana from two Delta employees at the Detroit airport, the statement said. Authorities allege those individuals were participating in a separate smuggling operation between Detroit and Houston.
A Twitter post from the airline said Delta fully cooperated with federal authorities in their investigation.
"Delta does not tolerate employees found using their position for illegal activity and these employees have been suspended without pay," the post said. "Additional disciplinary action could be taken pending the final outcome of the investigation."
All 12 suspects were charged with possession of controlled substances with intent to distribute and conspiracy.