(CBS)  The head of Chiquita Brands International says his company paid murderous paramilitaries in Colombia to save the lives of its banana operation employees there.

In his first television interview on the subject, Fernando Aguirre also tells 60 Minutes correspondent Steve Kroft that any murders committed by the paramilitaries are the fault of the gunman and not Chiquita. Kroft's report will be broadcast this Sunday, May 11, at 7 p.m. ET/PT.

"These were extortion payments. These were payments that had to be paid to protect the lives of our employees,” says Aguirre, “Either you pay or your people get killed," he says of the payments to United Self Defense Forces of Colombia (AUC), which was designated a terrorist group by the U.S. in 2001. "There was a very strong signal that if the company would not make payments that things would happen and since they had already killed 50…employees of the company…they were going to do it again, no question about it," he tells Kroft.

A former AUC leader, Salvatore Mancuso, interviewed by Kroft in a Colombian prison, says it wasn't just Chiquita that paid his group what he calls "taxes." "All companies in the banana region paid. For instance, there was Dole and Del Monte [Fresh Del Monte Produce], which I believe are American companies," says Mancuso.

Both companies deny making such payments. But Mancuso, also indicted for cocaine trafficking in the U.S., said he welcomes U.S. inquiry. "I am taking the opportunity to invite…the Department of Justice so that they can come and so I can tell them all that they want to know from us," he tells Kroft.

The heavily armed AUC held sway over most of the northern part of Colombia where Chiquita's plantations have operated for decades. They came into power by driving off Marxist rebels and their sympathizers to whom Chiquita also made payments years ago in a land beset by warfare that included civilian massacres the government could do little to stop. "These lands were lands where there was no law. It was impossible for the government to protect the employees," says Aguirre.

Once the AUC was declared a terrorist group, Chiquita's payments became illegal under U.S. law.

Chiquita disclosed the payments to the U.S. Department of Justice and agreed to pay a $25 million fine, or about half the profits it made since the AUC was designated a terrorist group.

Now the families of Colombians killed by the paramilitaries have hired lawyers like Terry Collingsworth to sue Chiquita for the deaths of their relatives. Collingsworth says Chiquita had to have known that the money they paid to AUC, about $1.7 million over several years, was being used to buy bullets and guns that killed many unarmed civilians. "If you provide knowing substantial assistance to someone who then goes out and kills someone, or terrorizes…you’re also guilty," says Collingsworth. He says Chiquita should have left Colombia rather than continue making payments for seven years.

In 2004, Chiquita sold the company's Colombian operations. Aguirre says his company couldn't have just abandoned its employees during the conflict and that, "The responsibility of any murders are the responsibility of the people…who pulled the trigger."