Speaking with state house correspondents after meeting with President Muhammadu Buhari on Tuesday, Dan-Ali said Shekau had been disguising with masks to evade arrest.
He maintained that the military had overpowered the sect, and expressed the belief that its leader will be arrested “as soon as possible”.
“The spiritual headquarters has been ransacked and vandalised, and Shekau is on the run,” he said.
“He may be hiding in one of the enclaves of Sambisa forest, which we are dominating. We have opened up the place we are using the place as a training area. We shall be patrolling and be ransacking that forest for the whereabouts of Shekau.
“If you have been opportune to go to Sambisa forest, you will know we have dominated the whole stronghold of the sect, their spiritual headquarters has been destroyed, and is now occupied being by our armed forces.
“I believe it’s just a matter of time, it took America about seven to 10 years to get Bin Laden, so we will get Shekau as soon as possible.”
Asked to comment on the claims of the military that Shekau had been killed, he said, “Let me tell you categorically, these insurgents have a way of disguising with masks. It’s possible that there are many (Shekaus), but we are looking for the real one.
“He has been using mask to give the impression that he has been killed, so that we can relax, but we will not relax until we get him.”
Shekau has embarrassed the military on a number of occasions. Each time the army pronounces him dead, he resurfaces in audio or video messages.
In September, Leo Irabor, theater commander of Operation Lafiya Dole, a military task force in the north-east, boasted troops had killed the individual originally identified as Shekau, as well as his impostor.
He described as “a façade” videos of Shekau released by Boko Haram.
“I can confirm to you that the original Shekau was killed, the second Shekau was killed,” he had said.
“They released videos to prove that they are still active, but that’s just a facade.”
However, less than five months after making the utterance, Irabor said he would “grab Shekau by his balls” if he knew his whereabouts.
In September 2014 when the military announced his obituary, the boastful militant leader released a video to debunk the claim.
“They said I am dead, but here I am. The world should know that I am alive and will only die at the appointed time. Everybody should be judged according to the dictates of his conscience,” he had said.
“What I am doing is written in the Holy Qur’an and the Hadith and I will not stop. I challenge all the clerics of the world to question my deeds. Those underrating my capacity should have a rethink. I will never allow democracy to thrive.
“The concept of government of the people by the people for the people will never be possible and will never exist. Democracy shall be replaced only by the government of Allah, from Allah and for Allah.”