In an interview with ABC's George Stephanopoulos, President Donald Trump said he had never called the FBI in "his whole life," but he offered to place undercover FBI agents in one of his casinos in the 1980s.

"I'll tell you what, I've seen a lot of things over my life. I don't think in my whole life I've ever called the FBI. In my whole life," he said

And last summer Trump denounced his former lawyer Michael Cohen for "flipping" on him by making a plea deal with prosecutors, and even said flipping should be illegal.

Yet Trump himself has cooperated with law enforcement at least twice going back to the 1980s.

He reportedly testified in a sales tax evasion scheme to avoid prosecution, and also worked with the FBI to come up with a plan to crack down on organized crime activity in his casinos.

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In an interview with ABC's George Stephanopoulos, President Donald Trump said he had never called the FBI in "his whole life," but he worked with the FBI on a plan to place undercover agents in his Atlantic City casino in the 1980s.

"I'll tell you what, I've seen a lot of things over my life. I don't think in my whole life I've ever called the FBI. In my whole life," he said when Stephanopoulos asked if he would contact the FBI if a foreign government offered him dirt on a political opponent. "You don't call the FBI. You throw somebody out of your office, you do whatever you do."

"Oh, I think I'd want to hear it," Trump said. "It's not an interference. They have information. I think I'd take it."

Trump's admission stunned the country, given that a political campaign accepting help from a foreign government is illegal, and Trump's own FBI director Christopher Wray said in previous congressional testimony that politicians approached by foreign actors should contact the FBI.

Read more: 'I think I'd take it': Trump says he might not go to the FBI if a foreign government like Russia offered him dirt on political opponents

And last August, Trump decried his former personal lawyer Michael Cohen "flipping" on him by pleading guilty to 8 federal crimes and went as far to say flipping should be "outlawed," in an interview with Fox News.

But Trump himself has not only has a documented history of contacting the FBI, has a long history of cooperating with law enforcement going back to the 1980s.

"I know all about flipping. For 30, 40 years I have been watching flippers," he told "Fox & Friends" host Ainsley Earhardt in the Fox interview.

Cohen is currently serving a 36-month prison sentence after pleading guilty to charges of tax evasion, bank fraud, making illegal corporate and campaign contributions to influence the 2016 election, and lying to Congress

"If you can say something bad about Donald Trump and you will go down to two years or three years...most people are going to do that," Trump said of Cohen's plea deal. "And I have seen it many times. I have had many friends involved in this stuff. It's called flipping and it almost ought to be illegal."

Yet, on at least two occasions in the 1980s, Trump reportedly testified to avoid persecution, and actively offered to cooperate with law enforcement to quash criminal activity.

The casino

President Donald Trump at hi Taj Mahal casino in New Jersey. Chaarles Rex Arbogast/AP

As BuzzFeed News reported in January 2017, Trump offered to "fully cooperate" with the FBI to monitor potential organized activity in his Atlantic City casinos as far back as 1981.

An FBI memo from that year details Trump and his brother Robert raising concerns with the Bureau about building a casino in the New Jersey gambling hotspot given reports of widespread mob activity, and discussing plans to place undercover agents in the casino.

"Trump advised Agents that he had read in the press media and had heard from various acquaintances that Organized Crime elements were known to operate in Atlantic City," a memo from the fall of 1981 said.

Read more: Donald Trump's casino business in Atlantic City was a 'protracted failure'

"Trump stated in order to show that he was willing to fully cooperate with the FBI, he suggested that they use undercover agents within the casino," the memo read. "At this point, [an agent] initiated steps with the Newark office ... to begin planning an undercover proposal concerning the proposed Trump casino."

Buzzfeed reported that while the memos revealed that FBI did, in fact, come up with an elaborate plan to place agents in Trump's casino, it's not clear whether it actually went into motion.

The jewelry store

The Bulgari store on Fifth Avenue in New York City. Google Maps

In the mid-1980s, Trump was one of several celebrities caught up in a sales tax evasion scheme with luxury Fifth Avenue jewelry boutique Bulgari.

To avoid the hefty New York state and city sales taxes on high-end jewelry, authorities said customers would order jewelry to be shipped to a different state without such steep sales taxes, The New York Times reported in 1985.

The store would then ship an empty box to an out-of-state address while customers walked out of the store with the items without having paid the proper taxes.

Read more: A Connecticut mansion once owned by Donald Trump is on the market at a 29% discount. Take a look inside the $38.5 million estate and its private putting green.

Prosecutors said Trump avoided paying sales tax on about $65,000 worth of jewelry, the United Press International reported in 1986. Henry Kissinger, Frank Sinatra, and Mary Tyler Moore were also named in the probe.

When authorities in New York state caught onto the scheme, Trump reportedly testified against the employees at Bulgari Jewelry in order to protect himself from criminal prosecution that could have put his real estate license in jeopardy.

A former state prosecutor told ABC News that Trump and other customers helped build the case against the store. The boutique and two of its executives ended up pleading guilty to criminal charges, and paid $2 million in fines, The New York Times reported at the time.

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