Singapore's horse racing community was in shock yesterday after receiving news that former Kranji-based apprentice jockey Chung Wah Thong was shot dead in a brutal murder in Penang.

Chung, a 28-year-old Malaysian who rode briefly at the Singapore Turf Club (STC) earlier this year, was killed along with three others, according to Malaysian news reports.

Besides Chung, the other victims were his 55-year-old mother Tan Saw Sim, his two-year-old son known as Ah Bee, and Toh Hock Choon, 50.

All four had been sleeping in a container, the makeshift living quarters of the chicken-processing factory in Batu Maung that Toh operated.

The killer is understood to be a male relative, who is believed to have been on drugs.

He later fled in a pick-up truck before abandoning the vehicle some 70km from the scene. Police have launched a manhunt for him.

State Criminal Investigation Department chief Datuk Razaruddin Husain said police were alerted to the incident at about 2.55am and initial investigations showed that the suspect could have flown into a rage after he could not get money to buy drugs.

Chung was in Penang to assist his mother with her business for the Hari Raya period. His wife, Jess Tan, was in George Town with their one-year-old daughter when the incident occurred.

The STC yesterday expressed its deepest condolences to the bereaved family.

Chung, who won 30 races including the Malaysian Group 1 Selangor Gold Cup last year, had relocated to the Republic in January and was indentured to Singaporean trainer Leslie Khoo before he was slapped with a one-year disqualification in March on a handling charge for his ride aboard the Alwin Tan-trained Real Hero in February.

In 31 starts here, Chung recorded three third-place finishes.

Khoo was in state of disbelief at the tragedy. He said: "It's so senseless and to lose his son and his mother ... makes it even more senseless.

"WT (Wah Thong) was a quiet boy but he worked hard at the stables. Unfortunately, he got one year, but we'll never get to know him more than the couple of months he was with us.

"My sincerest condolences to his family."

Former three-time Singapore champion apprentice jockey Mark Ewe was equally distraught.

He said: "He was a few years younger than me, but he was a friend of mine as we're both Penang boys.

"We often met for dinner and we would always have a good time. He was quiet but he also liked to joke and loved his wife and son."