By Orla Guerin
BBC News, Islamabad
Bin Laden is believed to be somewhere along the Pakistan-Afghan border
A Taliban detainee in Pakistan claims to have information about Osama Bin Laden's whereabouts in January or February of this year.
His claims cannot be verified, but a leading American expert says his account should be investigated.
The detainee claims to have met Osama Bin Laden numerous times before 9/11.
He claims that in January or February he met a trusted contact who had seen Bin Laden about 15 to 20 days earlier in Afghanistan.
"In 2009, in January or February I met this friend of mine. He said he had come from meeting Sheikh Osama, and he could arrange for me to meet him," he said.
"He helps al-Qaeda people coming from other countries to get to the sheikh, so he can advise them on whatever they are planning for Europe or other places.
"The sheikh doesn't stay in any one place. That guy came from Ghazni, so I think that's where the sheikh was."
The province of Ghazni in eastern Afghanistan has an increasingly strong Taliban presence.
Large parts of the province are no-go areas for coalition and Afghan forces.
He says he declined the invitation to travel to meet Bin Laden because he was afraid of compromising his security, if he was captured by the police or the army.
"If I had met him, the first question they would have asked would be where have you met him, and I would have had more problems and it would have created problems for them [al-Qaeda]."
According to a Pakistani security official the detainee has close ties with leaders of the Taliban in Pakistan and Afghanistan, and was involved in kidnapping and fund-raising operations in the north-western city of Peshawar.
The detainee, who cannot be named for legal reasons, said that militants were avoiding Pakistani territory because of the risk of US drone attacks.
"Pakistan at this time is not convenient for us to stay in because a lot of our senior people are being martyred in drone attacks," he said.
We were given access to him twice in the past month. He spoke at length and in detail, painting a picture of close co-operation between the Taliban and al-Qaeda.
A Pakistani interrogator was listening as he spoke.
His account suits Pakistan, which maintains that Bin Laden is not on its soil, though Britain and the US think otherwise.
But US counter-terrorism expert Bruce Riedel, a former CIA analyst, says his story is "a very important lead, that ought to be tracked down."
"The entire Western intelligence community, CIA and MI6, have been looking for OBL [Osama Bin Laden] for the last seven years, and haven't come upon a source of information like this.
"So, if it's true - a big 'if' - this is an extraordinary and important story," he said.
"We know Osama Bin Laden is alive. We know that he is living somewhere in the badlands along the border with Pakistan and Afghanistan.
"What's extraordinary about this story is we have someone who has come forward and said, really for the first time, 'I met with Osama Bin Laden and I had the opportunity to met him again in the recent past'."
Active and healthy
The detainee claims that Bin Laden is well, though there has been speculation for years that he was in poor health.
"What my associate told me was that he is fresh, and doing well," he said.
He also claims the al-Qaeda leader is still active, training instructors who in turn train others.
"The information I have is that he provides training to special people. There are training centres in homes, and all the teachers are first trained by the Sheikh. Then they go and teach the classes."
The detainee's account raises a lot of questions - among them, what were his motives for talking.
Western interrogators may have lots of questions they would like to ask, but so far the detainee has been out of their reach.