Before Underbelly, there was Abe Saffron, Australia's first and most notorious Godfather, who ruled the underworld like a modern Caesar.

For 40 years, the so-called 'Mr Sin' was at the forefront of organised crime. Now his son Alan is breaking ranks, receiving death threats over his tell-all book, about the King of the Cross.

"Never killed anyone, the two things he was probably against was violence and killing," says Alan of his father Abe Saffron.

That's at odds with the infamous 1975 abduction and murder of Kings Cross community activist, Juanita Nielsen. Many suspected Abe was involved.

"Was your father involved in the murder of Juanita Nielsen? asks Anna Coren.

"Absolutely not, absolutely not. I talk about that very clearly in the book. And I detail down to the last detail because the person who did it told me exactly how he did it," answers Alan.

Almost 30 years ago, six children and one adult were killed on the ghost train in Sydney's Luna Park.

Speculation arose that Saffron, who coveted the amusement park, was behind the blaze, a claim reignited by a niece of Abe's who claims he was responsible.

"The Luna Park Fire was a tragic accident and I'm really, really sorry that my cousin came up with this theory which, God knows where she got it from," says Alan.

"The Police and Fire Department did a very thorough investigation and I was privy to seeing the suspected arson report. They determined in the report that in those days a kerosene based paint was used in the Luna Park, then there was an electrical fault in the Ghost train. It sparked on the kerosene based paint - up it went."

At the age of 30, Alan was offered the keys to the kingdom - the heir apparent, summonsed to take on the family business. He turned him down.

Alan made his escape to Los Angeles, forging his own career as a talent agent.

"It just became very clear to me that I have to go out on my own. I have to do it. But it wasn't on my own. It's so incredible, I went all the way to America and there was still his influence continuing on in me," says Alan.

But Alan was to feel the full force of his fathers disappointment upon his death in 2006 at the age of 86.

"He left me $500,000. Now, a lot of Australians will say that is an awful lot - it is a lot of money, but when you put $500,000 against $25 million?" says Alan.

"Plus he put conditions in - if I dispute the will, I get nothing."

But his father took some secrets to his grave.

"I am 100 per cent sure there's at least $5, $10 or more million somewhere out there. Where is the money?" asks Alan.

One of Alan's biggest regrets is the death of his mother, a death he blames on a marriage where her love was never returned.

"What I think eventually killed her was the loss of will to live. She realised he's never going to change," explains Alan.

And so it is for his mother, as Alan bought flowers for her on a bitter morning in July. Abe Saffron's only son is having the last word.

"I don't see it as bad blood, I see it as a great disappointment. I see it as hurt, very serious hurt. Devastation in some way. But I still love him," says Alan.

"I don't know, he's my father. He's the only one I've got. I don't have another father. I don't know anything different. I still have that love. I will always have that love."

"In a lot of respects he was a very good gentle man. In a lot of other respects he was Satan - gentle Satan."

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