There are two sides of the coin as to why the Pakistanis were accused of ball tampering.
1. Reverse swing was new and it bewildered the English leading to accusations.
2. They really did tamper with the ball. Sidhu has said on tv that it is not unknown among cricketers that tampering is some thing which took place by lot of if not all teams. Pakistanis mastered it and Indians would struggle after the drinks breaks in Sharjah.
There is no proof to the tampering accusations and so its unresolved