Over the years Sebastian Marroquin -- formerly Juan Pablo Escobar -- has rejected dozens of offers from Hollywood to help tell the story of his notorious late father, gunned down by police in 1993.

But Marroquin, who changed his name and relocated to Buenos Aires to start a new life, has finally spoken out in "Sins of My Father", Nicolas Entel's powerful entry to Sundance's World Documentary Competition.

"A producer friend in Colombia suggested making a documentary about Pablo Escobar," Argentine film-maker Entel told AFP.

"I was looking to do something new, from a different point of view and it was then that I had the idea of telling the story through Escobar's only son.

"I spent six months trying to convince him to take part. He had already turned down more than 50 offers because most of them wanted to exploit the name Escobar and glamorize the life of a gangster."

Juan Pablo Escobar was 16 when he decided -- shortly after the bloody death of his father -- to change his name and move to Argentina with his mother.

Now a 30-something architect, Marroquin appears in the film as a tormented soul, torn between feeling love for the man he once knew as his father and disgust at the horrific crimes he committed, which included ordering the murders of several thousand people according to some estimates.

If Marroquin appears calm, "it's because he has lost the right to be angry," Entel told AFP.

"If you play a dirty trick on me and I say 'I'm going to kill you', you know it's a figure of speech," Entel said. "If Sebastian says something like that then he knows that tomorrow the newspapers are going to say that the son of Pablo Escobar threatened to kill someone."

Entel's documentary follows Marroquin as he attempts to seek reconciliation with the children of Rodrigo Lara Bonilla, Colombia's former justice minister, and Luis Carlos Galan, a presidential candidate, both of whom were murdered at the behest of Escobar.

The scene where Marroquin comes fact to face with the children of his father's victims is the documentary's most powerful moment.

"For me, it was very important to concentrate on the children, on the new generation," Entel said.