However, captured Afghan soldiers were interrogated by the British chief engineer, Colonel Thompson, to whom they revealed that all of the gates into Ghazni had been sealed with rocks and debris except the Kabul Gate which was in the north. Thompson spied on the gate and observed an Afghan courier entering the city which confirmed what the prisoners had said. Further inspection showed the gate to be lightly guarded and inadequately defended. It was then decided to attack the city through the Kabul gate. The British went around the city and camped on the north side facing the Kabul gate.