relieving Mohammad Shahid, the former personal secretary to Chief Minister Harish Rawat, in connection with the liquor sting operation under pressure from DoPT would not suffice, said State BJP president Tirath Singh Rawat on Wednesday, adding that only a CBI probe would unravel the mystery. “CBI probe into the sensitive matter is a must in view of the integrity of the Chief Minister himself remaining under cloud,” he said, during his ongoing Kumaon trip.