By Hamid Ismailov
BBC Central Asia and Caucusus service
Tahir Yuldashev's men have been accused of numerous suicide attacks
A leading Uzbek militant, Tahir Yuldashev, is widely believed to have been killed in a missile strike in the tribal area of South Waziristan in August.
A militant spokesman has denied his death but Pakistani officials say he was killed in August - around the same time as Pakistan's former Taliban chief, Baitullah Mehsud met his death.
The two men were friends and both had fearsome reputations.
What Tahir Yuldashev brought to the militant nexus were numerous other Uzbek insurgents who operated across Pakistan's tribal areas - and are even suspected of making forays over the border to launch attacks on Afghan soil.
I first met him in the stunning city of Namangan in the lush Ferghana valley when making a programme about the rise of Islam in Uzbekistan. This historic city became the focus of his move to create an Islamic republic in Uzbekistan.
It was during this meeting that he told me: "This town is called Namangan, but you can also call it Islamabad."
Many years later he had been driven out of Uzbekistan and was heading a brutal band of insurgents in north-west Pakistan.
Uzbek militants in Pakistan are renowned for their fanaticism. They are believed to have strong links with al-Qaeda and have been known to operate as "hired guns".
Tahir Yuldashev's men have been accused of numerous suicide attacks and of killing hundreds of tribal elders in Pakistan over the years.
His militants carried out attacks on Pakistani forces in the tribal belt and are believed to have taken part in the Red Mosque siege in 2007 in which dozens of people were killed.
Nobody really knows exactly how many Uzbek militants are in Pakistan. Estimates vary wildly: from 500 to 5,000. Not all Uzbeks there are active militants - some are merely supporters.
At that first meeting in 1992, the tall and bearded Tahir, then aged 26, was dressed in a simple kaftan and light blue track suit bottoms.
Militants roam freely in the tribal region of South Waziristan
He took me through the crowded town of Namangan, shouting orders to someone on the other side of the street.
At that age Tahir Yuldashev was the founder of the Adolat, or the Justice movement, a gang of Muslim youths who were using what can only be described as draconian methods of punishment in that part of north-eastern Uzbekistan.
I had heard that thieves and prostitutes would be seated on donkeys, face-to-tail, and paraded around town. Others were beaten with sticks or tied to poles for passers-by to spit in their faces.
These vigilantes wore green armbands and would drag off any woman daring to wear a short skirt and shave her head.
A few months earlier, on 9 December 1991, Tahir Yuldashev and thousands of his supporters crowded into the city square in Namangan and demanded that Uzbekistan be made an Islamic republic.
From that day on he would always be associated with a form of Islamist militancy.
Mr Yuldashev became a wanted man for repeatedly criticising Uzbekistan's President Islam Karimov and in 1999 he was sentenced to death for being behind a series of bomb attacks in the Uzbek capital, Tashkent - which were mired in controversy.
At this point Tahir Yuldashev had fled Uzbekistan. He and his followers began calling themselves the Islamic Movement of Uzbekistan, the IMU.
The group operated from bases inside Tajikistan and Taliban-controlled Afghanistan where al-Qaeda leader Osama Bin Laden and Taliban head Mullah Mohammad Omar were supportive of the IMU's plans to Islamicise Central Asia.
The movement boasted that it was several thousand-strong and fought alongside the Taliban during Afghanistan's civil war.
In the wake of 9/11, the IMU's base near the northern town of Mazar-e-Sharif was bombed by US warplanes.
Over the years the BBC Uzbek service received many electronic messages with Tahir Yuldashev's speeches and statements from Waziristan in Pakistan, where he was based with his core of die-hard militants.
Moment of candour
I remember the last time I saw Tahir Yuldashev back in 1997 on a flight to Iran for an Islamic conference.
During the meeting he came to talk to me off the record. In a rare moment of candour he told me that he was well provided for as a child and was the son of a goods depot director.
He then said that the first time he became infatuated with Islam was after secondary school where he excelled and then went on to study at college.
In that time he became a militant leader whose sphere of influence spread from Uzbekistan to Afghanistan and now Pakistan.
Analysts say his reported death will almost certainly leave a gaping hole in the leadership.
But his group it seems is already working on ensuring that their struggle continues by spreading their militant philosophy to the next generation.