Sherlock Holmes finds another clue on reaching the spot. It leads him to a potential witness. The witness informs him that “I reached the spot at 2 A.M. Since it was dark I was carrying a lantern. The lantern has 50 ml of oil when I lit it up at 1 A.M at the station. The lantern burns 1 ml of oil every 2 minute. At 2:45 I saw a person walking down the lane toward main gate. I asked him to stop. He started running and I followed. I finally nabbed him at 2:55 and in lantern light I saw his face. He punched me and ran away” Sherlock accuses him of lying. Why??