DW: Finding out information about a person like Mullah Omar must have been difficult. How did the Taliban react to a Western journalist asking questions?
Bette Dam: The Taliban were not easy to speak to about the whereabouts of Mullah Omar. They were very secretive about it. Now I know why. They were actually hiding the fact that he had no influence, that he was not in Pakistan, that he was not in control of the insurgency. The Taliban made up the story of their powerful leader. It was all fake news.
After encountering these difficulties, how did you go about digging up the truth?
I did many interviews with several sources. Then I went to the Afghan secret service in Kabul. I spoke to three generals. One still believed that Mullah Omar was living in Pakistan. But the other two believed that he was in Afghanistan.
And in those conversations, a name repeatedly kept coming up. It was of Omar's bodyguard and I wrote it down, but I was not able to reach him at the time. He had been arrested. When I eventually found him, he was not in a real prison though. The Secret Service of Afghanistan had offered him a safe house.
I got hold of a picture of Jabbar Omari before I went to meet him at this house. That was important because I needed to identify him. When I saw him for the first time, I really wondered whether it was really the person I was looking for. But it was him. After working for five years on Mullah Omar, it was very special to see the man who had been with him for a long time, who is a reservoir of information. I was now able to see Mullah Omar at least through his eyes and ask him questions.
What was it like talking to the man who once promised to give his life for Omar?
The interview was not so easy. I think he was afraid of me, afraid that I had very strong opinions on Mullah Omar. He was very apprehensive. It took me an hour or two to convince him but then we spoke for six hours. He told me about the details of Mullah Omar's life and how they spent their days together.
It was very difficult for him to speak about the people who were involved, which is understandable. And it was very difficult for him to reveal the name of the village where Omar was hiding.
Although I had already found out the name of the village, I asked him a couple of times about it. I said: "Can you please share the name? I will not write it down."
But then he said, "OK, show me the map" and I had a map with me from that area. I pointed my finger to the village. He then looked at me and closed the map, saying: "What is your next question?" So that is how close I got with this information.
How did you verify the information from the various sources?
I had already received a lot of information on this story from the local secret service who gave me the village's name and who told me how Omari was operating.
And another thing which is very interesting is that after 9/11 many Taliban fighters went to this particular area in Zabul. And it was common knowledge that Mullah Omar was among them.
Then there are other sources. For example, there was another messenger coming and going between another city and this village, so we had that man identified. I had the opportunity to cross-check his existence and what the Taliban were thinking about him and his role. And there was a former spokesperson of the Taliban who also wrote a book about this particular period in Pashtu. So we had that translated.
The information you gathered suggests that Mullah Omar basically lived around the corner from a major US military base which would be an embarrassment. Have you gotten any reaction from US authorities?
I did request the Pentagon to comment. They didn't. But I'm sure something will happen. Some former CIA people are now knocking on my door to speak to me and that's very interesting. And I think it will be very good to create another document to see what the result of all this is.
You also talked to some of the people working in the US military base Wolverine in Zabul. What did they say?
I spoke to the intelligence officer of that camp whose job it is to find terrorists. First, I just let him speak about his work. He said: "We are basically only focusing on keeping the road between Kabul and Kandahar open because we have so many things on our plate. So our focus is to get our military out if necessary."
So other issues, like where Mullah Omar was, were not on his agenda. When I asked him "Did you ever look for Mullah Omar?" he said: "Why would I look for Mullah Omar? He is, of course, in a country that is friendly to him, so he is in Pakistan."
Your book provoked a huge outcry worldwide. Were you aiming for that?
It was very difficult for me to know what would happen. The Dutch book was published four weeks ago. That was immediately a best-seller. I did not expect this because Afghanistan is out of the news. So many publishers rejected my book, saying: "Oh no, we are talking about ISIS now." But I just thought, "OK fine. I think it's an important story. I go and see what I can do."
I am happy that the world is talking about it now and is debating the intelligence the Americans have, for example. I want people to question the war on terror: what do we actually know about it, and what do we know about the people who are on these most wanted lists that Washington has prepared.
But I also hope that the book will be translated in many languages, so that we continue this discussion in the world about the global war on terror. Perhaps it inspires other journalists to do more cross-checking on claims from Washington or claims from Afghanistan or Pakistan.
Bette Dam is a Dutch journalist and author. She has spent several years working in Afghanistan, using her expertise to write her book 'A Man And A Motorcycle' on Hamid Karzai. 'Searching For An Enemy' is her third book.
The interview has been edited and condensed for clarity.