Lahore, 2008. From a distance, Dalbir Kaur can see her brother, sitting hunched up in his dark and dank cell. She recognises him, even though they haven't met for 18 years - not since he disappeared from their home in Bhikhiwind in Punjab's Tarn Taran district in 1990. And here he is now, locked in Kot Lakhpat Jail in Lahore, Pakistan.

It's not a joyous reunion. Sarabjit is going to be hanged. Pakistan President General Pervez Musharraf has upheld his death sentence. Kaur and other members have travelled to Pakistan to make a last ditch effort for his release.

Mumbai, 2015. Kaur, 62, does a double take when she watches actor Randeep Hooda in prison uniform, sitting inside a makeshift jail. "He looked exactly the way Sarabjit looked in prison uniform. For a split second I felt I was meeting my brother. My blood pressure shot up and I felt dizzy," Kaur recalls.

She had been invited to witness the shooting of the film Sarbjit. To be released on Friday, it tells the story of the Punjab farmer who was imprisoned and died in Pakistan, and his sister's struggle in vain for his release. Hooda plays Sarabjit, and Aishwarya Rai Bachchan his sister.

For years, Kaur determinedly campaigned for his release, and homecoming. When he returned home, it was in a coffin. Sarabjit was attacked on April 26, 2013, in the high security jail, allegedly by fellow prisoners. He died six days later. A special aircraft carried his body to Amritsar, from where it was taken to his village in Bhikhiwind on the Indo-Pakistan border.

It was here that Sarabjit, who lost his mother when he was 22, helped his father till their land. Kaur says their father looked at Sarabjit's photograph every night before going to bed and wished to meet him at least once before he died. He breathed his last in 1998.

Her younger brother was 25 when he suddenly disappeared from home. Then one day, they received a letter from Sarabjit. He said he was being held in a Pakistan jail under the false name of Manjit Singh and a case had been filed against him.

The worried family was happy to know that he was alive. "At that time we thought we would bring him back from Pakistan with the help of the Indian government," Kaur says.

According to the family, Sarabjit was arrested by the Pakistan Rangers after he accidentally strayed into an unmarked border area in a state of drunkenness. The Pakistan police held him responsible for bomb blasts in Lahore and Faisalabad that killed 14 people in 1990. He was tried and convicted by the Supreme Court of Pakistan. Sentenced to death in 1991, his execution was repeatedly deferred by the Pakistan government.

Sarabjit never stood a chance in court. Kaur lists the legal shortcomings - there was no identification parade; his confession was written in Urdu, which Sarabjit could not read or write; the signature was in Urdu; no forensic report was placed showing evidence of fingerprints.

"Our petition was rejected in the Pakistan Supreme Court since there was no lawyer to represent my father," says Swapandeep Kaur, his elder daughter who was two when Sarabjit disappeared. His younger daughter, Poonam, was 23 days old.

Kaur approached almost everybody she thought could help secure his release - from legislators to ministers to government officials and film stars. She even met the then Prime Minister, P.V. Narasimha Rao.

"My biggest regret is that Narasimha ji did not take proper steps to secure my brother's release. If he had taken an initiative, I would have got my brother back," she says, wiping off her tears. "Relations between the two countries were not bad then and he could have secured his release."

The family filed five mercy petitions in Pakistan, all of which were rejected. "In April 2008, when Musharraf rejected my brother's appeal for clemency, I met Rahul Gandhi, Sonia Gandhi and Pranab Mukherjee, who was the external affairs minister, in Delhi. I faxed a letter to Musharraf, following which a stay was granted for three months."

In 2011, Kaur travelled to Pakistan to plead with the authorities for his release. "Ministers and officials all promised help but eventually did nothing."

But every time someone was released from Pakistan, she rushed to the border with the hope of getting some news of her brother.

Hope clashed with despair. In 2012, there were reports that Sarabjit was about to be released. A storm of protest from Islamic groups in Pakistan followed, and Islamabad announced that the prisoner released was someone called Surjeet Singh.

Ten months later, Sarabjit was attacked, allegedly with bricks, sharp metal sheets, iron rods and blades. He was admitted to the Jinnah Hospital in Lahore, and died there on May 2, 2013.

Kaur feels Sarabjit's "murder" was planned. "A few months before his death, Sarabjit had sent us a letter through another lawyer, saying that he was being slow poisoned and his vital organs were malfunctioning. He was physically and mentally tortured. Probably he understood the end was near," she says.

Sarabjit's widow, Sukhpreet, and Poonam live with Kaur in Bhikhiwind. Swapandeep is married and lives in Jalandhar. The Punjab government, which announced an ex gratia payment of Rs 1 crore for the family, gave the elder daughter a government job and the younger one a gas agency.

For Hooda, the role of Sarabjit was one of his most "difficult assignments" and it took him a while to get into the character of the Punjabi farmer. "I used to sit at home in chains and write letters, thinking I was writing to my sister. I would go through the solitude of things, talk to myself and think what it felt like to be in darkness," he says.

Kaur is happy with the way her character has been portrayed by Rai Bachchan. "Aishwarya looks the way I did when I was young. I was thin and fair and had very long hair. I enjoyed wearing lipstick and a bindi and dressing well. I stopped dressing up when my brother's appeal for mercy was rejected by the Pakistan Supreme Court."

As the film gears up for release, Kaur hopes it will be able to highlight the plight of Indian prisoners in Pakistan. Her struggle for the release of prisoners - on both sides of the border - continues.

A few days ago, Kaur went to Delhi to receive the body of Kirpal Singh who'd died in a Pakistan jail.

"I met external affairs minister Sushma Swaraj and home minister Rajnath Singh and gave them a list of 90 Indian prisoners held in Pakistani jails. I also requested them to release Pakistan prisoners from Indian jails," she says. "My brother has suffered, but others should not suffer like him."