Brigadier Ali Khan, the Pakistani officer detained for his alleged links with the banned extremist group Hizb ut-Tahrir, had been highly critical of the Pakistani army's high command over its relationship with the US, reports BBC Urdu's Asif Farooqi.
Colleagues of Brig Ali Khan, who did not want to be named because they are still in service, say he was an officer with a distinguished career, a gold-medallist who was consistently promoted.
But he had been exerting strong pressure on the top echelons of Pakistan's military to stop co-operating with American forces in the fight against Taliban and al-Qaeda insurgents, army officers who served with the brigadier during his 32-year career told the BBC.
Pakistan's military spokesman Major General Athar Abbas said that there was compelling evidence against the brigadier owing to his contacts with the banned group.
The brigadier joined the army in 1979 and came from a humble background in Pakistan's Punjab province.
But his career hit a roadblock when he openly criticised Gen Pervez Musharraf when he was still army chief-of-staff.
Passed over
At an army course at a prestigious military college in Quetta, Brig Khan asked Gen Musharraf why he would not divulge the details of an agreement with the US to the Pakistani public.
The brigadier also said the "limits" of co-operation with the US on "the war on terror" should be clearly defined.
A senior military officer who was present at the occasion told the BBC that Gen Musharraf was clearly unhappy with the questions, and had asked around about the officer.
A few weeks later, the army promotion board held its regular meeting under Gen Musharraf. Brig Ali, who had been tipped for promotion to major general, was passed over.
Successive promotion boards rejected Brig Ali while his colleagues and subordinates continued to rise up the promotion ladder, overtaking him. Indeed, to date, Brig Khan is the oldest brigadier in the Pakistani army.
His colleagues thought he would be unable to withstand a career going nowhere and would seek early retirement. But they were soon proved wrong. The brigadier told his colleagues he had more to accomplish in his job.
It soon became clear what he meant by that. Brig Khan started writing letters to army generals, some of whom were his former colleagues, with suggestions on how to become "self reliant" and "to purge the army of the American influence".
He told senior officers such as Gen Ashfaq Pervez Kayani that Pakistan's "unconditional" support to the Americans was causing resentment in the lower ranks of the army.
He said that "growing" American involvement in Pakistan - especially in its military affairs - was negatively affecting the morale of the armed forces.
An officer who received one of these letters said that after coming to know that Gen Kayani wanted this sort of correspondence to end, he spoke with his former colleague and politely told him to refrain from annoying the senior leadership.
"But Ali wouldn't listen to us. He thought his input was necessary to save the institution he was serving and loved," the officer said.
Anger vented
Brig Ali even wrote to the President Asif Ali Zardari suggesting ways to make Pakistan economically self-reliant by freeing the country of American aid.
After the US Special Forces raid on Osama Bin Laden's compound on 2 May, Brig Khan finally got the opportunity to vent his anger.
On 5 May, he was invited to a meeting by his former student and now his boss, Lieutenant General Javed Iqbal at the army headquarters.
The question that officers were asked at this meeting was how to pursue an inquiry into the 2 May raid.One officer present in the meeting said all had been going well until it was Brig Khan's turn to speak. In his opinion, the culprits who had hidden Bin Laden and allowed the Americans to get away with breaching Pakistan's sovereignty were to be found within the army.
Gen Javed Iqbal was furious at the end of the meeting. As it turned out, Brig Khan's views were not those of a lone wolf - he had managed to persuade some of his fellow officers of the veracity of his case.
Gen Iqbal promptly told the corps commanders what had happened the following day at a meeting chaired by Gen Kayani. That same evening Brig Khan was arrested.
Army officers who have worked with the brigadier say that nobody who knows him seriously believes that he has been involved in anything illegal.
"But the problem is that his anti-American views and [opinions on] self reliance were getting popular with middle and lower ranking officers," one remarked.
In an interview with the BBC's Urdu service Maj Gen Athar Abbas commented: "The army is a cult in itself, so it's intolerant towards any other cult within".
It looks as is Brig Khan's cult was growing too rapidly and too dangerously.
BBC News - Brigadier Ali Khan: Pakistan's dissenting army officer