Yes, they were hiding bin Laden and that was the causa belli. The USA gave an ultimatum to the Taliban, which they denied, and the invasion happened shortly after.
After the battle of Tora Bora, a lot of al-Qaeda members managed to flee into Pakistan and further east, so you could say that the reason for the invasion into Afghanistan ended there.
Yes, they were hiding bin Laden and that was the causa belli. The USA gave an ultimatum to the Taliban, which they denied, and the invasion happened shortly after.
After the battle of Tora Bora, a lot of al-Qaeda members managed to flee into Pakistan and further east, so you could say that the reason for the invasion into Afghanistan ended there.