A DELIVERY worker's ''amateurish attempt'' to rob a San Po Kong villa has landed him in jail for four years. The District Court's Deputy Judge Christie passed the sentence on Kwok Sai-man, 26, yesterday after finding him guilty of assault with intent to rob. Evidence called by prosecutor Lisa Remedios revealed that Kwok gained entry to the Yan Wo Apartment at 4.25 am on May 19, 1993, under the pretext of renting a room. However, when cleaner Chan Sau-fan showed him to a room and quoted the price, Kwok said it was too expensive. Kwok drew out a melon knife from his shorts and declared robbery when Ms Chan was about to open the villa's main door for Kwok. Ms Chan rushed into one of the rooms and shouted ''robbery'' out of the window. A police officer on patrol downstairs heard the shout and arrested Kwok. Solicitor James Li submitted in mitigation for Kwok that it was an amateurish attempt instead of a premeditated one. He said no actual force was used.