Tsang Kwok-wai, 36, a police officer for 16 years, took part in yesterday's search for illegal immigrants in Hung Mui Kuk Country Park. He is a sergeant in the Police Tactical Unit and lives in Tuen Mun with his wife, a son and a daughter. What's on your mind? The need to arrest all the illegal immigrants in the park as soon as possible. I hope our efforts will pay off and that hikers will be more safe and happier when they climb the mountain. I am on the noon shift today. I started working at 11.30 this morning and will work another 12 hours. Do you always work such long hours? No. It is just because of today's special operation. Usually, we work eight hours a day. Is it a tough job? Not really because I have just finished working at the border in Lok Ma Chau. My duties there involved searching for illegal immigrants. From last December to March, our team in Lok Ma Chau arrested 208 illegal immigrants. Compared with the duty there, today's job is not very tough. How many illegal immigrants are sneaking in nowadays? There are fewer illegal immigrants now and most of them came from northern provinces of China like Jiangsu where conditions are more primitive. Unlike those in the past who usually committed well-organised crimes, they just want to get jobs here. Most of them work at construction sites as casual workers. Sometimes, they commit small crimes like thefts, burglaries and robberies when they have no money. There are fewer coming in by speedboat and committing major crime with guns. Judging from your experience, where is the most popular place for secret camps? Along the water and behind thick bushes. Our operation today is mainly going along a stream. They need water to survive. What do you think about being a member of the Police Tactical Unit? It's a tough job. Much tougher than uniformed police. The training is very demanding and the nature of the job is very harsh. Why then did you join the unit? Every policeman needs to join the unit for at least a year. After that, we can go back to the uniformed unit and resume normal duties. What do you think about women joining the unit? Although their training is less demanding, they are very useful.