"People would ask you to make purchases for them, possibly maybe a car or a chalet, possibly a nice watch. So you would also cater to the client in that regard and then deliver it to them upon their choosing," Birkenfeld explained.
"And what would be their choosing?" Kroft asked.
"It could be in their hotel room. It could be in maybe another country. Could be there in Geneva," Birkenfeld said.
"So you were sort of not just a banker but also a personal shopper?" Kroft asked.
"If you will…at a concierge level," Birkenfeld said.
Birkenfeld claims his motives in going to the Justice Department were mostly altruistic. He offered to wear a wire to gather evidence against high-level UBS executives in exchange for full immunity for his transgressions, but the negotiations broke down.
And Birkenfeld neglected to tell them about his dealings with California real estate developer Igor Olenicoff, who was his biggest client. Birkenfeld helped Olenicoff hide $200 million by introducing him to a consultant who specialized in creating shell companies and sham entities that concealed the ownership of the UBS accounts.
"I don't sign people's tax returns, so what they do with their taxes is not my business. I'm a banker," Birkenfeld argued.
"So you would steer them to somebody who would help them hide their money?" Kroft asked.
"You would recommend them to these service providers. That's correct," Birkenfeld said.
"You must have known deep down that it was illegal," Kroft remarked.
"When you came into the U.S. you felt uncomfortable. That's correct," Birkenfeld said.
But as a gesture of good will, Birkenfeld did give the Justice Department, Senate investigators, IRS agents, and the SEC lots of information about UBS and its secret activities.
"Any transaction that happened on an account was held deep in the vault and sealed until the client came to pick it up personally. Then they would either take it with them, which was generally not the case, or they would tell you to shred it, which we would do on behalf of the client," Birkenfeld said.
Birkenfeld told Kroft that clients were forbidden to have online accounts and that they didn't get statements in the mail.
"So if somebody wanted to know how much money they had in the bank and how their investments were doing, they had to go to Switzerland?" Kroft asked.
"Or maybe see their banker when they came to the U.S.," Birkenfeld explained.
It was those visits to the U.S. which Birkenfeld told the government about that ultimately got UBS in so much trouble. The bank would sponsor lavish events like yacht races in Newport and the Art Basel art festival in Miami Beach to attract wealthy Americans.
Then it flew in its bankers from Switzerland to mingle and to try and drum up new clients and conduct business with existing ones. Because the Swiss bankers weren't licensed to conduct business in the United States, it was a clear violation of American banking laws on U.S. soil, and Birkenfeld provided internal documents that proved the length that UBS would go to in order to avoid detection.
"'Call it a vacation rather than a business trip.' Rather than saying, 'Oh, yes, I'm coming to see my private clients here in the United States. And I'm coming in from Zurich, Switzerland,'" Birkenfeld said.
Asked if he brought records into the country when coming to the U.S., Birkenfeld told Kroft, "Generally, no. I did not. My colleagues brought in encrypted laptops. … So that even if they were discovered you couldn't see what was inside the computers, which were portfolios of the clients and they were product offerings for the clients."
"They were going out of their way to cover their tracks," said Thomas Perrelli, the associate attorney general of the United States
Perrelli says Birkenfeld was not the only person who provided valuable information to the investigation, but he says Birkenfeld's evidence that UBS executives encouraged illegal behavior was the bank's Achilles' heel.
"They would bring checks or sometimes they would actually carry money from one client to the next, all with the purpose of disguising and avoiding detection of large transfers of money," Perrelli told Kroft.
Perrelli added, "It was certainly surprising that there would be a unit within a major bank that would be behaving in that way."
"And there was?" Kroft asked.
"And there was. And we subsequently learned that senior officials knew about this. They knew it was wrong. They called it 'toxic waste.' But it was very profitable and they didn't stop doing it," Perrelli replied.