Last week our jaw-dropping exposé of the presidential hopeful revealed a man so delusional he claimed the world’s most beautiful women pestered him for sex.

Here, in the second and final extract, we expose Trump’s troubling mafia friendships and how a lucrative deal to build Trump Tower came with protection of senior figures in the mob...

Donald Trump, pictured with his former wife Ivana, built Trump Tower in New York in the 1980s

There are two rules of business that Donald Trump swears by: ‘Be paranoid – because they are gonna try to fleece you’ and ‘Get even – if somebody screws you, you screw ’em back ten times over.’

And his taste for revenge is not limited to disloyal employees or bad business partners. In 2000, Trump picked on his own family.

Soon after Trump’s father, Fred Snr, died at the age of 93, Fred’s grandson Fred III – Donald’s nephew – had a baby son, William.

The baby suffered seizures and the medical bills that followed ran to nearly a third of a million dollars.

Trump’s younger brother, Robert, assured Fred that all the medical bills would be covered.

When Fred Snr’s will was filed, however, so little was left to Fred III’s side of the family, they felt as though they had been disinherited.

The will was contested, with a claim that it had been ‘procured by fraud and undue influence’ by Trump and the other surviving siblings. Donald’s reaction was swift and vengeful.

A week after the lawsuit was filed, Fred III received a letter stating that all medical benefits would cease on May 1.

For little William, that was a potential death sentence. When pressed about whether it could appear cold-hearted to withdraw the medical insurance of a sickly child, Trump did not waver.

‘I can’t help that. It’s cold when someone sues my father,’ he replied.

Trump later said that the cases had been settled ‘very amicably’.

Trump’s act of vengeance on his blood relatives caused deep division within his family.

He did, however, develop a close relationship with someone else, a figure who became a kind of second father.

The notorious Roy Cohn was one of the most vicious and heartless men who ever lived in America – a mentor who also believed, as it happened, that revenge was the best policy.

Cohn had been the chief lawyer for Senator Joseph McCarthy, infamous for his communist witch hunts.

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The 58-storey New York skyscraper Trump Tower, pictured, was allegedly built with the help of the mafia

Trump’s steadily deepening relationship with Cohn would link him to mob-owned construction companies at a time when other builders were begging the FBI to crack down on the mafia.

In Cohn, Trump had someone who could be ‘vicious’ on his behalf and who, he said, looking back in 2005, ‘would brutalise for you.’

Trump first hired Cohn to sue the federal government after it investigated claims of racial bias involving a number of apartment block owners, including Trump.

At Trump’s Shore Haven apartments in New York, the superintendent told a white woman she could have her pick of two units shortly after a black woman had been told there were no vacancies.

Trump did rent to African Americans and others not considered white, but only in certain buildings.

The Justice Department sued Trump. Cohn filed a lawsuit demanding £60 million in damages from the federal government.

This marked a key moment in Trump’s career, as he adopted the tactic that would be a core tenet of his 2016 presidential bid: hitting back harder when he feels attacked.

‘I’d rather fight than fold, because as soon as you fold once, you get the reputation’, he said.

But faced with a case in which neither facts nor the law were on his side, Trump did fold – and settle.

Trump would learn that Cohn came with another benefit. Hiring him could ensure Trump’s Manhattan building projects moved smoothly.

Trump, left, developed a close relationship with his attorney Roy Cohn, right, who was previously chief lawyer for Senator Joseph McCarthy

Among Cohn’s other clients were two of America’s most powerful mafia figures, who controlled key unions in New York City.

In 1978, Trump had hired mobbed-up construction firms to erect Trump Tower. Instead of building a high-rise skeleton of steel girders, Trump chose ready-mix concrete.

It has advantages such as avoiding costly fireproofing for steel girders.

Trump used it for other buildings, but in other ways it was a curious choice as the material had to be poured quickly, which made developers vulnerable to union work stoppages.

The truck drivers – teamsters – controlled the vehicles delivering the ready-mix. The construction unions controlled the construction site gate.

The concrete workers and carpenters controlled the pouring and making of forms. At the top, the mob controlled the unions.

Trump bought his Manhattan ready-mix from a company called S & A Concrete, secretly owned by mafia chieftains Anthony ‘Fat Tony’ Salerno and Paul Castellano – Cohn’s clients.

With Cohn as his fixer, Trump had no worries that the mafia bosses would have the unions stop work on Trump Tower.

Indeed, when the cement workers went on strike in the summer of 1982, the concrete continued to flow at the tower.

Just as revealing was Trump’s association with John Cody, the corrupt head of Teamsters Local 282.

Cody, under indictment when he ordered the city-wide strike in 1982, directed that concrete deliveries continue to Trump Tower. Cody told one journalist: ‘Donald liked to deal with me through Roy Cohn.’

Cody’s son, Michael, told me that his father was every bit the notorious racketeer people believed him to be.

He said that, as a boy, he listened in when Trump called his father, imploring Cody to make sure concrete flowed steadily at Trump Tower so he would not go broke before it was finished.

While Cody did not get a Trump Tower apartment, as the FBI suspected – an especially gorgeous woman friend did. She had no known job and attributed her lavish lifestyle to the kindness of friends.

Cohn introduced Trump to Mafia boss Anthony ‘Fat Tony’ Salerno, centre, who provided concrete for Trump Tower

She bought three Trump Tower apartments directly under the triplex where Donald and his then wife, Ivana, lived. Cody invested £60,000 in the woman’s apartments and stayed there often.

Trump helped the woman get a $2 million mortgage to pay for the three apartments, one of which she modified to include the only indoor swimming pool in the tower.

She said she got the mortgage from a bank that Trump recommended, without filling out an application form or showing financial details.

After Cody was convicted of racketeering, imprisoned, and no longer in control of the union, Trump sued the woman for $250,000 for alteration work. She countersued for $20million.

Her court papers accused Trump of taking kickbacks from contractors and that this could ‘be the basis of a criminal proceeding’ against Trump.

Trump, despite his boast of never settling lawsuits, quickly settled, paying the woman $350,000.

He has testified that he hardly knew those involved, and that there was nothing improper in his dealings with either the woman or John Cody.

Federal prosecutors soon brought a major case against eight mobsters. The charges included inflating the price of concrete for Trump’s East 61st Street apartment building.

In 1986, Salerno and seven others, including the head of the concrete workers union, were convicted in a racketeering trial that also featured claims of murder and payoffs.

The chief trial prosecutor told the judge that the defendants were ‘directing the largest and most vicious criminal business in the history of the United States.’

Trump boasts that when he applied for a casino owner’s licence in 1981, he persuaded the New Jersey attorney general to limit the investigation of his background.

It was perhaps the most lucrative negotiation of Trump’s life, one that would embarrass state officials a decade later when Trump’s involvement with mobsters, mob associates and swindlers became clearer.

Even after he got his casino licence, Trump continued to have relationships that should have cost him his gambling permit.

His murkiest dealings involved a major cocaine and marijuana drug trafficker named Joseph Weichselbaum – for whom Trump did unusual favours.

Weichselbaum was already a twice-convicted felon with convictions for car theft and embezzlement, when, in 1982, he and his brother landed the contract to provide a helicopter service to ferry high rollers to and from Trump casinos in Atlantic City.

Trump is no drug user. He doesn’t drink or smoke. But it was open knowledge in Atlantic City that high rollers could get anything they wanted.

Those who brought lots of cash could get, for a price, whatever they wanted – be it illicit sex, drugs, or anything else.

In 1985 Weichselbaum was indicted for drug trafficking. One shipment alone involved three-quarters of a ton of marijuana.

Bob Libutti, right with Trump, a major gambler at Trump Plaza, is said to have known of law-breaking at Trump’s casino

Strangely Trump retained the firm for his casino shuttles and to service his personal helicopter, paying more than $2 million a year.

The Weichselbaum case was moved to New Jersey and assigned to Judge Maryanne Trump Barry – Trump’s older sister.

She removed herself, thereby sending a powerful message that this was a case with potential to embarrass the bench.

Trump wrote a letter to the replacement judge asking for leniency. In contrast to lengthy sentences passed on bit players on the same indictment, Weichselbaum got three years.

While he was behind bars, Weichselbaum’s girlfriend bought two adjoining 39th-storey Trump Tower apartments.

In spring this year, I asked Trump why he wrote that letter for Weichselbaum. Trump said he ‘hardly knew’ the man and didn’t remember anything about him.

When I reminded Trump that he said on national television just a few months earlier that he had ‘the world’s greatest memory,’ Trump just said that ‘that was long ago’.

Much more recently, Trump chose to work with a convicted art thief who goes by the name Joey No Socks.

His real name is Joseph Cinque, and he is president of the American Academy of Hospitality Sciences.

It awarded the Trump International Golf Links, a breathtaking seaside course in Aberdeen, its coveted Six Star Diamond Award.

The awards are chosen by its board of trustees – which for years included none other than Donald J. Trump, who held the title Ambassador Extraordinaire.

Recent trustees include Ivanka, Trump’s daughter, and his son Donald Jr.

In 1989, New York police found a trove of stolen art in Cinque’s apartment. After Trump announced his campaign for President, he was asked about his association with Cinque.

Trump said he hardly knew him. ‘If a guy’s going to give you an award, you take it,’ he said.

Another man Trump has trouble remembering is Russian-born Felix Sater.

Asked about him in 2015, Trump said he would not recognise Sater. Yet in 2009, when the Trump SoHo opened in Lower Manhattan, he was filmed alongside Sater, a violent convicted felon and swindler who in 2005 helped Trump make two big development deals in Denver.

Sater has been convicted of stabbing a man in the face with the stem of a margarita glass and has admitted taking part in a 1998 mafia-inspired £25 million stock swindle that benefited him and the Genovese and Gambino crime families.

Trump, pictured, has been nominated as the Republican candidate for the US Presidential election

A further dubious Trump friend is Bob Libutti. Of the 33 million people who played in Atlantic City during its mid-1980s golden age, he was Trump’s best customer.

Trump treated Libutti like a friend, lavished gifts on him – and repeatedly tried to seduce his divorced daughter.

Furious that a married man would attempt to bed his daughter, Libutti confronted Trump, ordering him to stop asking her out.

‘Donald, I’ll f*****g pull your balls from your legs,’ he threatened. Trump backed off, and Libutti continued pouring money into Trump Plaza.

Leonard ‘Leo’ Cortellino and Charles Ricciardi Snr, both associates of the Gambino crime family, had told Robert Walker, a state police detective working undercover, about a bookmaking operation they ran in Atlantic City that benefited the notorious mafia don John Gotti.

The bookies told Walker that they knew both Libutti and his brother-in-law.

They said that Libutti ‘was in Donald Trump’s pockets’ – meaning Libutti knew of serious rule violations at the Trump casino that would interest the regulators.

Had these claims been investigated and proven, they would surely have cost Trump his casino licence, but Trump’s relationship with Libutti was just another part of his long history of flouting the supposedly strict regulations of New Jersey casinos.

Trump is remarkably agile at doing as he chooses and getting away with it.

© David Cay Johnston, 2016