By Syed Shoaib Hasan
BBC News, Karachi
When Abid Hunzala's wife was informed that he had blown himself up in a suicide attack, she was not surprised.
Abid's mission ended with an attack on this bus in Sargodha
A month earlier, she had received a letter from Abid, making it clear he was not coming back.
The letter tells Fatima that a certain amount for money will be delivered to her to help her get by in the short term.
In the long term, the letter says, "you should get remarried, as it will be the best thing for you and our son".
Abid's letter also tells her to give his best wishes to his mother, "and tell her to pray for me... I am going on a mission for God."
The letter was handed over to detectives investigating militant suspects in Karachi after a raid on Abid's house.
They already knew a fair bit about him. His father and elder brother had been killed years ago fighting in Indian-administered Kashmir.
Abid studied at an Islamabad madrassa before going to fight in Afghanistan after the 11 September 2001 attacks on New York and Washington.
He returned and continued his religious education at Islamabad's radical Red mosque.
He was arrested there last July after security forces stormed the mosque. He was later released.
When police acquired Abid's letter to his mother last September, they issued an alert to try to prevent his suicide attack.
Abid was arrested at Islamabad's Red Mosque, and then released
But on 1 November, Abid rode a motorbike into a Pakistan air force bus in the eastern town of Sargodha.
He blew himself up and killed 11 people, included seven air force officers.
"It was quite ingenious, the way they did it," an investigator later told the BBC. The bike had two large tin drums, like those used by local milkmen, attached on either side.
These were filled with explosives wired to the horn, which was the detonator.
"The usual practice is to check the man [or men] to see if they are wearing [suicide-bomb] jackets," the investigator said.
"Abid was checked along the road but nobody thought of checking the drums."
"We have been able to arrest most of the remaining members of his cell," the investigator said.
Police say the cell was led by a retired army major, Ehsan-ul-Haq. This is not the first time that a security official has been involved in militancy.
And the names of the organisations being mentioned with suicide attacks, such as Jaish-e-Mohammad and Lashkar-e-Jhangvi are also familiar.
Police say this Kashmiri suspect was plotting a sectarian attack
But security officials say they are changing their ways of operating.
"Experts believe that there has been a fragmentation of the jihadi organizations," an intelligence official told the BBC.
"What has actually happened can better be described as decentralisation and amalgamation," the official said.
"When they [the militants] attack Shia targets we say they are Lashkar-e-Jhangvi, when they carry out assassination attempts on senior government leaders it is Jaish-e-Mohammad or Harkatul Mujahideen.
"If it is near the tribal regions or targeted against security forces, it is the Taleban," the official said.
"In fact, all these have proven to be obsolete stereotypes in the light of subsequent investigations."
The militants, security officials agree, now operate in small cells that have a great deal of autonomy from the upper command structure of the organization.
The security forces face an uphill struggle
"This means that when we break a cell, they have no idea as to the leaders' whereabouts," another intelligence official says.
"But what is even more frustrating and dangerous is that they will not know about another cell operating in the same area, or against the same target."
Much of the focus in recent years has been on the Waziristan tribal area.
Waziristan serves primarily as a safe hideout, the second intelligence officer says.
"Even as a training area it is over rated... all you need is a couple of rooms to train and arm a suicide bomber.
In the past, most of the militants were Pashtun tribesmen, from Waziristan and other tribal areas that straddle the Afghan-Pakistan border. But that is no longer true.
"There are as many Punjabis and Muhajirs, as there were prior to 9/11... Kashmiris and ethnic Baloch are also present," the second intelligence officer says.
In a recent plot by Sunni Muslims to attack Shias in Karachi, the alleged ringleader was a Kashmiri.
"Now prior to 9/11, the involvement of Kashmiris in sectarian attacks was almost unheard of... and now here is one actually leading the way."
It makes for an uphill task for the security forces.
It is compounded by what most security officials call the government's "see no evil, hear no evil" approach to militants.
"The jihadis recruitment is at an all-time high, and it is principally due to lack of will on the part of the government," the investigator says.
He is referring to the lack of enforcement of a section of Pakistan's anti-terrorism laws.
When a person under suspicion is released from custody, he is required to provide police with a detailed daily account of his movements, saying where he went, whom he met and when he returned, the official says.
But it hardly ever happens.
"The released men bribe the local police station so they don't have to call in everyday," the official explains.
"After the payment, they are free to travel as they wish."
The investigator says the ex-militants use this time to travel around the country giving lectures and sermons at certain mosques and madrassas.
"Everybody knows this has gone on since 2005," the official says.
"In Punjab province alone, over 300 militants have been released during this time. They know they are being watched so they do not carry out any act of violence themselves."
But what these men are doing, the official argues, is more dangerous.
"They are producing an army of militants like none before. Previously, at least, they had handlers in the state machinery. Now, they say, we only answer to Allah."