On November 21, five days before the fourth anniversary of the 2008 Mumbai terror strike that killed 126 people, India executed the only attacker captured alive by the police. Ajmal Kasab, found guilty of murder and waging war against India and scores of other offenses, was hung with little fanfare in the early hours of of the morning and buried at Yerwada Jail in Pune. Indians, it seemed, wanted to put the attack and the last remaining culprit behind them.But though Kasab was the only attacker in Indian custody he was not the only living person suspected of involvement in the Mumbai attack. Others remain in Pakistan. Seven alleged leaders of the attack are in custody while others are at large. Kasab could have been a key witness in the case against the seven who are in custody, including Zakiur Rehman Lakhvi, a co-founder and second-in-command of the terrorist group Lashkar-e-Taiba. Several times over the past few years the slow moving Pakistani prosecution asked for Kasab’s testimony to be heard in court, to no avail.Lakhvi and six other LeT operatives have been in custody in Pakistan since December 2008 and were formally charged by the Anti-Terrorism Court in November 2009. Lakhvi was described as the “mastermind” behind the attacks; the others were “facilitators” or “handlers.”But the case against them is proceeding at a snail’s pace. Half a dozen judges have overseen the case but each has stepped down or been forced aside for unknown reasons. Lakhvi, who is being “treated like a state guest and not a terrorist” according to an intelligence official, apparently fathered a child with his youngest wife while in jail. High-ranking Pakistani politicians including Interior Minister Rehman Malik have acknowledged the role played by Lakhvi and his co-conspirators in the Mumbai attack but deny that the Pakistani authorities are not interested in bringing the alleged terrorists to justice. Malik added that the process is complicated.Kasab is dead now and his testimony will never be heard in court in Pakistan. He might have had a few interesting things to say. According to lawyers involved in the case against Lakhvi and his co-accused, India executed the only remaining piece of evidence. As Pakistani journalist Amir Mir writes, “The defence lawyers of the accused are quite hopeful that with the hanging of Ajmal Kasab, who was in fact the only piece of evidence against the under-trial militants, all the seven suspects now stand a bright chance of getting the benefit of doubt to get off the hook.”This is more a convenient excuse to let Pakistan kill the case than a serious complaint. Kasab’s story might have shed some light on the inner workings of the LeT and the people behind the Mumbai attacks, but he was most certainly not the last piece of evidence in the case against the seven militants They and others like them, in one form or another, are protected by Pakistan’s deep state—a network of security minded and often Islamist intelligence and army officers, politicians, preachers, and community leaders who, together or separately, continue to influence Pakistani politics and foreign policy from the shadows. This group and its affiliates are responsible among other things for the occasional spectacular attack on India or assassination of a threatening and popular figure in Pakistan and the support of militant groups fighting in Afghanistan, among other strategies. American officials assume that at least some element of Pakistan’s deep state knew that Osama bin Laden had found refuge in Abbotabad and were happy to have him there. Pakistanis who make the deep state unhappy have a way of turning up dead.It is Pakistan’s deep state that is almost certainly responsible for the Mumbai attack, but that’s where the story ends. It won’t be proven in a Pakistani court. And, in all likelihood, just as in many other similar cases in the past, Lakhvi and his co-accused will be quietly released when the time is right. Pakistan’s deep state is completely and utterly convinced that it is engaged in a war of survival against a stronger, richer India. In that necessarily asymmetrical war, Pakistan must use every weapon it has. Islamist terrorism is one of its most effective weapons, and the Pakistani deep state is resolved never to give it up.