Mukhtar Ahmed Sheikh had made it possible to intercept the 26/11 death squad's calls — and prove Pakistan's role in the 2008 Mumbai terror attacks — but he remains nearly unknown. He neither received a medal, nor a reward. Instead, he was held in prison for three months on spurious charges.

Late on the night of 26/11, voices rose deep inside the bowels of a forgotten, colonial-era building in central Delhi. They echoed every secret word shared between the men who had come bearing death, every intimate whisper, every moment of killing. Through the night, a small group of men gathered inside the room where this strange haunting was underway, listening impassively for hour after hour, as 166 people were slaughtered. From inside the room, they saw 26/11 with the dispassion of gods, a whirlwind of blood that could be recorded, paused, rewound.

In August 2008, a Jammu and Kashmir Police agent had infiltrated the Lashkar-e-Taiba and planted 22 cellphone SIM cards on its commanders, destined for use in their operations across India. The cards were listed on an Intelligence Bureau watch list. When the 26/11 death squad powered-up their cellphones, a computer flickered on.

The one-time autorickshaw driver-turned-spy who made it possible to intercept the death squad's calls — and thus, to prove Pakistan's role in 26/11 — remains nearly unknown. He neither received a medal, nor a reward. Instead, he was held in prison for three months on spurious charges. His family lives in Kashmir, at continuous threat from terrorists.

In another other country, the story of Mukhtar Ahmed Sheikh and what happened to him would be a national scandal. It is, in more than one sense, the last ghost of 26/11.

Born in Srinagar's Rang Parestan neighbourhood, Mukhtar's introduction to the spy world was almost accidental. Pulled into the murderous world of Kashmir's insurgency in the mid-1990s, his brother lived for many years in the grey zone shared by the ideological jihadist, the drug dealer and the police informer. Early in 2006, the Hizbul Mujahideen executed Mukhtar's brother on allegations of passing on information to the police.

For years, Mukhtar had stayed away from Kashmir, choosing, instead, to make a living as an autorickshaw driver in Kolkata and Chennai. Later, he wanted revenge and was recruited by a police unit operating under then Inspector General of Police, SM Sahai.

The world of spies, in films, involves fast cars, luxury yachts, private jets and the obligatory starlets. In return for risking his life, Mukhtar earned Rs 1,500 a month as a follower — the lowest rank in the police, and the only one available to individuals without middle school qualifications.

From 2006, Sheikh made contact with mid-level Lashkar commanders in South Kashmir as well as Srinagar, providing safe houses, ferrying messages and arranging for transport. The organisation did not trust him, but Mukhtar passed every test. The police quietly ensured that the units he was working for were never targeted, at least when their agent might be suspected of having a role.

Then, in August 2008, came an unusual request: the organisation needed a large numbers of SIM cards that would work outside Kashmir. Mukhtar flew down to Kolkata, where he had friends from his days as an autorickshaw driver, and purchased 22 of them.

In Srinagar, Sahai, who had launched a series of path-breaking efforts to penetrate the Lashkar, run on little other than guile, wrote to the Intelligence Bureau's local station. The letter, despatched to then Intelligence Bureau station chief Arun Chaudhury, listed the numbers they had purchased and warned of their probable use outside the state.

Then 26/11 happened, and the Intelligence Bureau was able to listen in, in real time, to the attackers' conversations with their control room in Karachi, even though they were masked by fake voice-over-internet-protocol numbers. The calls included damning evidence on the role of top Lashkar commanders Muzammil Bhat and Zaki-ur-Rahman Lakhvi.

Even as Pakistan went public denying its link to the attackers and blaming the strikes on an Indian jihadist group instead, India had evidence to nail the lie.

Within days of 26/11, the Mumbai Police identified the SIM cards recovered from the 10-man death squad as having been purchased in West Bengal. Kolkata's Anti-Terrorism Squad was soon able to identify the man who bought them as an ethnic Kashmiri who once worked in the city and arranged for his friends to call him back. Early in December, Mukhtar was arrested.

Furious protests from the Jammu and Kashmir Police did nothing to help. The Intelligence Bureau knew the truth, but chose not to step in: Mukhtar would spend the next three months in prison without bail.

Intelligence Bureau insiders claim that the then chief, Nehchal Sandhu, was pushed by circumstance to allow Mukhtar to rot in jail. News that the SIM cards had been purchased in Kolkata had leaked via the Mumbai Police, and New Delhi couldn't afford to be seen as ignoring Pakistan's demands to identify the person who bought them.

At the same time, it is argued that Sandhu had to keep Mukhtar's actions secret, and thus allowed him to remain in prison while a strategy emerged.

Police officers in Kashmir, though, have a less charitable explanation.

"The truth is the spooks were hogging the limelight," one senior officer argued, "and didn't want it known that a bunch of nobodies had done a better job of penetrating the Lashkar-e-Taiba than they would have ever achieved."

Feuds between the Intelligence Bureau's Kashmir station and its counter-terrorism division in New Delhi, a third line of argument, sealed Mukhtar's fate. The counter-terrorism division, some officers claim, was furious it had been kept out of Sahai's Lashkar infiltration plans, and thus saw no reason to save Mukhtar.

There's no way of knowing the truth until files are opened, or a proper investigation is initiated. For three months, though, Mukhtar remained in prison, facing potential criminal trial for having facilitated the 26/11 attacks. He was finally released without charge, but was never rewarded with the medals anyone else with a similar intelligence coup to their credit would have received.

India's government, it seemed, was content not to have to add a Kashmiri Muslim hero to the 26/11 roster.

The least the Government of India could have done would have been to relocate his family and assign Mukhtar to a safer posting, but without patrons in New Delhi, there's been no one to push the case. Sahai and other officers involved in handling Mukhtar — those who came up with the whole operation to penetrate the Lashkar — weren't involved either.

Sahai is no longer involved in active police work and, instead, works on strategy issues with the National Security Council.

In the years since, though, Mukhtar has continued to work for the Jammu and Kashmir Police, volunteering for a role one officer described as "extremely high risk". In 2012, he figured in a series of covert operations targeting the Lashkar and the Hizbul Mujahideen.

"Every single day," the officer said, "I'm guessing he wakes up wondering if he's going to die, or hear that someone from his family has been killed."