Are you serious about investigating this murder? I doubt your seriousness in the first place. But in case you are really serious, please let me know as to what do you want to dig out exactly? By the way, have you formed an opinion about this murder? Remember, forming an opinion is much easier than investigating a crime.
You were offended by my doubt about your seriousness. But doubt is the door to investigation. If you can’t have a credible doubt, you can’t proceed with an investigation. Like Prime Minister Benazir Bhutto you may close the door by refusing to doubt a wife for the killing of her husband. Let me recall that as the Prime Minister she went to condole with a Federal Secretary who lost his son-in-law, a young captain of Pakistan Army, barely 20 days after the wedding. Obviously the She Prime Minister was moved by the plight of the family and when the senior bureaucrat apprised her of harassing interrogation of his innocent daughter, she promptly directed the police to find the killer or killers outside the house. Where you may ask? Well on the green Margalla Hills where the three bandits from Karachi intercepted the couple just past midnight. Interestingly the bandits were unarmed and when the young officer, who won the Sword of Honour at Kakul, drew the pistol a smart robber snatched it and shot him in turn. What a slap on the face of Pakistan Military Academy where the Sword of Honour is won by kids who can’t even handle a pistol.
Operating on the direction of the Prime Minister, and much within the prescribed limits, the investigators quickly and efficiently identified all the three amateur bandits by name and even nickname. Robbery, believe me, was not their living for all three were publicly recognized and branded terrorists.  They were key operators of MQM’s Terrorist Wing and were reportedly on summer vacations in Islamabad. That night they took the wrong hill road to Murree. Interior Ministry fully endorsed the young widow’s account by filling the three blanks. Pakistan, luckily, has a federal system and if a car stolen from Clifton can be sold in Khyber, why can’t a murder on the Margallas be traced to Lalu Khet. Eyewitness, after all, is an eyewitness. And the only eyewitness in this murder counted the killers as three.
The couple, by the survivor’s account, was relaxing in the back seat of the car (because they had no bedroom) when the bandits interrupted the love affair and asked for marriage documents. They had no interest in the man’s pocket or the woman’s jewelry. No, that’s not true. The fact, as reported by the eyewitness, is that they asked the couple to surrender the valuables and the silly husband resisted and reached out to his pistol.  Logical! How can an armed army officer take command from unarmed civilians without a showdown?         
What a handicap? While the robbers had no second weapon, the investigators had no second statement. They ought to rely on the only account, i.e.; the available truth --- or doubt.
That is how murder investigation proceeded under Benazir Bhutto and it won’t proceed any different under Pervez Musharraf.
In the prescribed investigation method we have no room for silly questions. As soon as we trace, rather transfer, the murder from the crime spot to the hideout of the enemy, we can swiftly assemble the jigsaw puzzle. And what is a jigsaw puzzle? Essentially it’s an image, a picture. Amateur Investigators like you instantly form a video image of the crime episode and then start searching for the fitting jigsaw pieces. Any thing that doesn’t match the perceived image is rejected outright. That is why, at the outset I asked you about any opinion you may have formed in your search for the truth. Because this time, you are not going to Lalu Khet, you are going to South Waziristan. The terrorist potential of Lalu Khet is none of your concern and even the victim herself had given a white certificate to Lalu Khet for the midnight slaughter near Karsaz on October 18 last. On May 12, on the very same airport road, named after King Faisal, you, rather everyone, were pointing a finger at Lalu-Khet but on October 18 you were in no such mood.
Obviously you are in no mood to discuss the May 12 massacre because our discussion shall focus on the most recent bloodshed. That means you give a free hand to the terrorists to achieve their specific political objectives. If that is the case, what is your grievance about this murder?  What is the riddle? There is no mystery. Terrorists struck. Period. Why bother investigation and Scotland Yard?
And what is investigation in Pakistan? My foot! Any person in authority can take it in any direction. The investigators can skin you alive but are not liable to answer any question once they reach a conclusion. You can’t question their brainwork. They are not required to arrest the culprits but are authorized to extract any evidence from anyone which they require to complete their jigsaw puzzles.  
See the three nervy terrorists from Karachi, with many murders to their bloody credit, were so frightened by the accidental killing on the Margalla that night that they simply vanished with the pistol and even threw the canvas holster in the woods. It was hanging on a small tree so as to be picked by the first passerby. They forgot there was a young woman behind. Let’s acknowledge, they were simple terrorists and bandits than rapists. After accidentally committing a heinous crime, they would not blot their careers and collect a bad name for their “Tanzeem” -- Organization. May 12 was just another accidental episode. It occurred in the ear of “Non-Reconciliation”. Now times have changed.    
I am willing to give you company to Waziristan and even to Uzbekistan but we must first determine the number of killers. In Karachi, not too long ago, an ex-Federal Minister Captain (Retired) Umer Asghan Khan was found hanging from the ceiling fan after signing a parting note. My investigation in that case began with the question as to how many persons do you need to retrieve a hanging body? I will not spell out the next question unless you have answered the first because without answering it you just can’t answer the consequent question: “How many persons do you need to hang a dead body to the ceiling fan?”
Some crimes are accidental but some have to be ‘organized’. That’s why English calls it ‘Organized Crime’.
No single killer will seek helping hands for hanging a body a few hours after the murder. All partners to the crime must be close to the spot when Umer Asghar decided to end his life and forgot to buy the sleeping pills. Why can’t a suicide be postponed for 24-hours? All those who were in that house that night are still there. No one thought of calling the Scotland Yard as the inquiry was thrown in the backyard.     
Now let me once again ask if you are still serious about investigating this murder? And what exactly puzzles you about this murder? Are you insisting to identify or pin point the lethal weapon that claimed her life? But why are you so particular about the weapon? What difference does it make whether it was a pistol or a bomb, a bullet or shrapnel? Or, as once claimed, just a crash against a lever? The cause of her death has to be found in the present state of affairs as well as the affairs of the State.  
No, I am not dismissing your questions outright. I will take due interest in any question that seeks to determine the minimum number of assassins assumed to be on the spot. But the importance of that question is intricately linked to the number of brains behind. Do you think that it was the handwork of a single group or more than one outfit waited for the opportunity?   
Of course, members of a single gang can always distribute the task among them and agree on a sequence of strikes in accordance with weapons at their disposal. You know that pistol shots preceded the explosion but the discussion is pointless because she lives no more. If you insist that there was no coordination between the two, we may discuss the matter further but kindly spell out your conclusion. All I know is that a person with a pistol would never stand by a suicide attacker of the same team unless he has no reason to live any more. But in that case, why can’t he acquire the killer jacket himself and be double sure of results. Live and let live or kill and get killed. Simple!
Obviously the assassins, even if only a couple, were in constant communication with each other while keeping a safe distance between them. None of the killers dared to enter the rally ground due to risk and limitation. Both were nearby the entry point but handicapped for the strike as she arrived in her armoured cruiser. The strike was deferred till the next opportunity. No, they did not hire the PPP workers for the farewell dance yet they found the black chance.  
Pistol was a preferred weapon over a telescopic rifle which requires a higher vantage point and is still not effective against a mobile target with visual obstructions. You simply can’t share the caution exercised by the assassins before the strike because none could afford to rub shoulders with her enthusiastic fans. In a crowd or jam packed audience, hidden metal on the body gets detected and these days with alarm.  
I can see you are fairly tired. And investigation is a tiring path without any short cuts. Besides we have to understand this murder before we can penalize the killers.