S2·E21 Episode 21

LIK, who is the partner of LUN, is suspected as the killer for three reasons. Firstly, his father runs a garage and thus LIK is good at car mechanics. Secondly LIK and LUN had quarrels over financial matters. Thirdly LIK and KWAN has filthy relationship behind LUN. However LIK has witness to prove that he was not with LUN when LUN was killed. The police go to question PO's family but no useful information is found. When they are on the way back to the headquarters, they meet a truck driver. His truck's tires went flat at Sap Shi Heung when LUN was killed. He saw a girl in red clothes driving a white car and leaving in a hurry. Thus they return to the scene where they find a burnt cigarette with lip prints on it.