"I never imagined there would be such a reaction, that it would be on every television channel and that we would receive media requests from all around the world," one of the reporters, Bastian Obermayer, 38, told AFP.
Germany's second-biggest daily in sales, the Sueddeutsche received from an anonymous source more than 11 million documents of the Panamanian law firm Mossack Fonseca that cast a harsh spotlight on the shady financial dealings of many of the world's rich and powerful.
Since Sunday, the revelations have brought down Iceland's prime minister Sigmundur David Gunnlaugsson, forced the resignation of a senior UEFA official and raised the heat on British Prime Minister David Cameron and Argentine President Mauricio Macri.
"We are still in the middle of the revelations," said the other journalist, who has a confusingly similar surname, Frederik Obermaier, 32, speaking at the newspaper's headquarters in Munich.
More From This Section
"In the coming days, there will be more topics that will make big headlines in many countries."
"If politicians really want to stop it, they must act now."
"We really need a hammer to destroy the system of offshore companies," he added, arguing that "the policy of small steps is not enough".
The data showed that, as national governments take steps against tax cheats, "they adapt, they find new ideas" to divert and hide their money, he said.
His colleague, Frederik Obermaier, was more reserved: "I think there is a lot of talk, but what will be done in the end is a different thing."
"I do not know if it's a man or a woman, or a group. I don't know the identity of this person," said Obermaier, adding however that "we have become a bit more familiar over the year" with the leaker.
At pains to protect their source, the journalists also declined to reveal whether the person had been in contact again or had reacted to the international reverberations.
But they were clear on the source's "moral" motivation, that the person "wants these crimes to be made public".