Daniel Pearl’s widow Mariane holds their son Adam as she arrives with Angelina Jolie for the premiere of A Mighty Heart in Cannes. (AP)

Amit Roy, the London correspondent of The Telegraph, was in Cannes on Monday during the world premiere of A Mighty Heart, a film on the kidnapping and beheading in Karachi of Daniel Pearl, The Wall Street Journal reporter based in Mumbai. Roy’s own documentary on Pearl, The Journalist and the Jihadi, made with London-based Ahmed Jamal as director, and much assistance from Delhi-based filmmaker Ramesh Sharma, has now been broadcast widely by HBO in the US.Roy’s account from Cannes:

While Jamal and I were travelling round the US doing our interviews, we were reduced to tears on two occasions: once, when we were with Mariane, and then when Daniel’s parents, Judea and Ruth Pearl, spoke to us of their reaction after they had learnt not only of the murder of their son but the circumstances of his death.

Today, there was a moment when the tears returned after one scene — and it is a tour de force.

When Angelina Jolie learns that her husband was not coming back, she rushes into her bedroom, bangs the door shut and lets out scream after scream.

I don’t think that I was the only one among the 2,500 journalists whose blood turned cold. What Mariane must have felt when she relived that moment!

Back in 1994, I was probably the first journalist to report that a public school educated British youth, Omar Sheikh, then 21, had been picked up over a botched kidnapping just outside Delhi.

Now fast forward 13 years.In the most glamorous day so far this year at Cannes, Angelina and Brad Pitt appeared together at a news conference after the world premiere of A Mighty Heart, a film shot substantially in India over a five-week period. Alongside Angelina was Mariane Pearl, whom she plays in the film.

Among other cast members on the panel was Irrfan Khan, in a role that could not be more different than the soft-spoken Bengali professor in Mira Nair’s The Namesake.

This time, he is cast as the Captain, the head of the Karachi CID, who is gentle with Mariane and, in fact, builds a trusting relationship with her but thinks nothing of torturing a Pakistani suspect in his efforts to extract intelligence about the missing American reporter. By common consent, Irrfan is utterly convincing.

Also present today was Archie Panjabi, a British-Indian actress who plays Asra Nomani, whose family emigrated from India to the US and who, in time, became a colleague of Daniel on the Journal.

The film’s director, Michael Winterbottom, who enjoys a justly high reputation in his native Britain, sat between Mariane and Angelina.

Mariane, a woman of exceptional goodness, is a valued friend, as is Archie. Jamal gave whatever help he could during the shooting of A Mighty Heart and even had a cameo role in the movie. Omar, who has been sentenced to death for the kidnapping, is now in a prison in Pakistan though all the indications are that President Musharraf does not want to go ahead with the execution.Omar was one of three released by India in exchange for the passengers of the hijacked Indian Airlines plane in 1999. A couple of years later, Omar, who was allowed to operate freely in Pakistan, had Daniel kidnapped and a week later the journalist was beheaded. His assassins added a touch of the macabre by videoing the act of decapitation and releasing it as a further act ofterror.

On balance, I would say that although the main protagonist, played wonderfully by Aly Khan, comes from a Pakistani fundamentalist background, the film avoids being anti-Pakistani. That is a considerable achievement. Nor is it anti-Islamic in any sense. However, Omar’s arrogance as a public school-educated boy shows through as well as his understated menace.

The notion that the kidnapping was an Indian plot done to embarrass Pakistan – the suggestion is put by a Pakistani minister – is examined and dismissed. So is speculation that Asra, because of her Indian origins, is an agent from India.

Some of the happier flashback scenes, when Mariane and Daniel, were enjoying the early days of their marriage in India – he had just been sent there by his paper as bureau chief for the region – were shot in India. Viewers will recognise the backdrop of the Taj Mahal Hotel and the Gateway of India as the couple take a little cruise in the Arabian Sea.

For the Karachi scenes in our documentary, Jamal went to Pakistan and shot the actual house in which the Pearls and Asra had stayed at the time of the kidnapping. Whoever did the location hunting for A Mighty Heart did marvellously well in finding a Pune residence which so closely resembles the Karachi property.

Another point I should make is that I know Mariane very well and whoever did make-up and styling has produced a startling lookalike. At today’s media conference, Mariane looked, well, like herself, but Angelina reverted to her own hairstyle and made sure she did not resemble the person whom she plays in the film.

The Daniel Pearl story is one of those tragedies that has left a scar on American consciousness. So, it is understandable that most of the questions today were from American journalists – several were “mother and making babies” type queries directed at Angelina.

One Indian journalist asked Angelina about the “security issues” that had dogged the shoot in India – a reference to the trouble caused by her bodyguards. She replied curtly that she had focused on the film because that had been the most important issue.

When I dealt with Mariane, I found she was always straight. Once she gave her word, she never went back. And, today, too, she was, as usual, refreshingly honest. How did Angelina get the role, she was asked. “I asked her to play it,” she said.

She had been reading a magazine and found she was moved by something Angelina had said. The two met and the role was Angelina’s. “‘Please do it,’” said Mariane. “‘You are the only person I know who can do it.’ I trusted her. She understood me. I am very fortunate she did it.”

Mariane was just over five months pregnant when her husband was taken. Angelina was about six months pregnant when serious discussions took place with Mariane.

“We have a lot different but a lot in common,” said Angelina. “I highly doubt there is anybody in this room who has more reason to hold hate inside herself than Mariane, and she doesn’t. That is, I think, a lesson for all of us.”

She admitted: “I was very, very nervous to get it right, but worked very, very hard to try. I did finally speak to her (Mariane) days after she saw it, and she told me it was all right. For her to tell me that she felt it was done right, I can’t tell you how much that means to me.”

How did Mariane feel now? Again, her honesty was moving. “I miss my husband,” she said. The film had not been made for money, added Mariane. “Everybody is doing it for the right reasons.”

Her deeper feelings about the film, which she saw a week ago and endorsed, were still very complex. But today she said she was aware her son, Adam, born a few weeks after Daniel’s death, would one day see the film about his father whom he would only know through the filter of history.

Pitt explained his own emotions: “We were very taken with Mariane’s story.”

He was impressed that although Mariane had reason to be filled with bitterness, she had gone out of her way to stress that at the time Daniel died, 10 others, all Pakistanis, had also lost their lives in Karachi.

Winterbottom said: “We tried to keep the story simple.”

Irrfan spoke highly of Winterbottom: “What I liked about him is that he was not instructing us but just following and letting us do what we wanted to do.”

With Pitt producing and Angelina in the starring role, A Mighty Heart is certain to do well at the American box office.

Pitt observed: “Everyone involved, of course, felt a great responsibility. We are very happy that the film maintained some of the dignity of Mariane and Daniel themselves.”