One week ago, six-year-old William Yau Zhen Zhong was still together with his family of five -- his parents, his seven-year-old elder brother and one-year-old baby sister.

However, after a celebratory dinner for his brother, Eric, on Jan 16, William or better known as 'Ah Zhong' went missing.

It was about 8.30pm that night when his father Yau Kok Kang, 32, and mother Goh Ying Ying, 25, left him with his siblings in their car.

Yau, a mechanic, and Goh thought that they could take a quick look for a new washing machine at an electrical shop along Jalan Putra Mahkota in Putra Heights, Subang Jaya.

That was the last time they saw William.

According to Eric, William had gone to look for their parents after their sister Cindy started crying.

The story of how William went missing is being told again by Yau and his wife as they are hoping they would be reunited with their son.

Public reaction on the matter has been overwhelming.

Photographs of William has gone viral online and are also being printed by good samaritans.

Non governmental organisations, private corporations, governmental bodies and political parties have also jumped onto the bandwagon in the search of William.

Deputy Prime Minister Tan Sri Muhyiddin Yassin had also appealed to all Malaysians to help search for the boy.

There were also several quarters, including Yau, who promised monetary reward in return for useful information on William. The amount has now snowballed to RM30,000.

Police said there were many speculations but investigators have only classified it as a "missing persons" case, ruling out kidnap.

No ransom calls have also been made so far.

However, they warned that those who kept William could face penalties under the law for taking away one's child from legal guardianship under Section 363 of the Penal Code.

The National Urgent Response (NUR) alert system was later triggered with as a special task force headed by the Subang Jaya police.

Police also said they’ve received many calls and SMSes, including those claiming to have seen the boy but none proved to be positive.

Pranksters and opportunists are apparently taking advantage of the situation to harass the family with some even resorting to threats and asking for ransom. This prompted the police to issue a warning to the public not to prey on the family's grief.

In the past week, police have continuously pleaded for anyone with information and stepped up efforts to search for the boy. They have looked through the CCTV footages and questioned more than a dozen witnesses.

Police teams, including sniffer dogs, are still going around the vicinity, including squatter areas, to track William's whereabouts.

Despite the little success so far, all hope is still not lost as you can still help the family find him.

William is about 110cm tall and has a scar on his left forehead. He was last seen in a yellow t-shirt.

Those with information can contact either the Subang Jaya police at 03-56319800, Sergeant Goh Lai Thang at 012-2197133, Putra Heights police station chief Sub Inspector Nordin Mustaffa at 012-3150775 or Yau at 016-9691616.

Help the Yau family find William. You can make a difference.