"Their images had been carved deeply in my mind. As long as they appeared, I was perfectly sure that I could recognize them," said Wang.

He even waited outside the shop at night, just to make sure he didn't miss out on the suspect. However, all the efforts came to nothing.

Then, Wang went to the suspect's home village of Donghua in Longtian town. He hired a car and parked it in a field not far away from the village house of the suspect and waited for his appearance.

To keep from being discovered, Wang drank little water to avoid going to the toilet and ate bread when hungry.

But after more than 10 days, the suspect still did not show up.

For 17 years, Wang has trekked to more than 10 provinces across the country in search of the murderer. Whenever he got a message about the whereabouts of the suspect, he rushed there without hesitation. Usually he stayed in one place for at least one week, and sometimes as long as nearly a month.

He has also searched for the murderer in a dozen foreign countries, including the US, Myanmar and Singapore.

Hunting the suspect for years has dragged the affluent family into heavy debt. Wang sold his property and divorced his wife. He held back the truth from his mother, saying he was doing business in other cities.

Every year during the Mid-Autumn Festival and on the eve of the Spring Festival, occasions when Chinese people return home for family reunions, Wang would go back to the aquatic product market in Guangzhou to wait for the murderer.

This was the most upsetting moment for him. "Every family was enjoying the time of reunion and firecrackers exploded in the air. I sat in a corner on the cold street, waiting for the suspect and never knowing when he would appear," said Wang.

Sometimes, when he was extremely disappointed and saw no hope of finding the suspect, he thought of committing suicide. But he did not do that, only because "my son's case has not ended, so I cannot die."