POLICE investigating the explosion in the Desa Palma area of Nilai on Dec 22 believe the suspect behind the incident has extensive technical and chemical knowledge, following the discovery of numerous improvised explosive devices and specialised equipment at his rented home.
Negeri Sembilan police chief Datuk Alzafny Ahmad said the findings strongly suggest that the house was used as a laboratory to manufacture homemade explosive devices. The conclusion was based on the seizure of a large number of IEDs and related components in various forms and sizes.
“Regarding developments in the Desa Palma explosion case, investigations led to the discovery of a large number of devices and components suspected to be IEDs in various forms and sizes at an identified house.
“Accordingly, the Royal Malaysia Police Bomb Disposal Unit was mobilised to carry out appropriate safety measures, including the controlled destruction of the devices on site using the in-situ method,” he said in a statement today.
Alzafny said the suspect, identified as Yeoh Hock Sun, 62, also known as “Ayang”, is believed to have specialised skills in producing explosives based on the equipment and materials seized. Among the items recovered were explosive detonators, highly flammable cleaning agents, carbon-based substances and elements containing sulphur.
“Investigations found that the suspect, also known as ‘Ayang’, has knowledge in the field of chemistry and previously worked at a pharmaceutical factory for three years, in addition to having knowledge in information technology (IT).
“Assessment of the explosives found showed that the materials were in perfect condition in terms of preparation and the devices used, including timers and sensors, and the activity is believed to have been carried out over the past six months,” he said during a press conference on the case.
Searches at the house uncovered 31 additional homemade explosive devices, all of which were subsequently destroyed by police for safety reasons. Alzafny said analysis by the Bomb Disposal Unit found that the explosives had a blast radius of up to 20 metres, with fragments capable of travelling as far as 30 metres.
“The materials used were nails and folding knives that were finely fragmented. So based on this preparation, we interpret that he has the knowledge to prepare complete and effective explosive devices,” he said.
Alzafny said Yeoh has been classified as an extremely dangerous individual and is now a high-priority suspect, as police believe he was directly involved in the preparation of the explosives. He also has a previous criminal record under Section 506 of the Penal Code for criminal intimidation.
Witness statements further indicated that the suspect was adept at concealing his identity, often wearing face masks or hats and even wigs when moving in public.
“Questioning of witnesses also found that he avoids crowds and displays aggressive behaviour. He has been separated from his wife, child and family for more than 30 years and has a history of assaulting his girlfriend,” Alzafny said, adding that police believe the suspect is still within the state.
So far, police have recorded statements from 14 witnesses and obtained closed-circuit television footage from the surrounding area for analysis. All seized items have been sent to the Chemistry Department and forensic units for further examination.
Alzafny said police are actively tracking down Yeoh, a Malaysian Chinese man whose last known address was at No 14, Jalan Sultan Petra, Kuala Krai, Kelantan, to assist with investigations.
“Police are seeking this individual to assist investigations under Section 4 of the Corrosive, Explosive and Scheduled Weapons Act 1958 and Section 435 of the Penal Code.
“Police give assurance that the security situation is under control,” he said.
However, he said precautionary measures have been intensified, particularly at events and programmes involving large crowds, as an early preventive step to avoid any untoward incidents.
Alzafny also urged the public to help locate the suspect and appealed to medical centres, clinics or pharmacies to report any suspicious individuals believed to be injured who may have sought treatment or purchased medication.
“This is because police believe that in the incident, this man sustained serious injuries… he is now in hiding and may be being sheltered,” he said, adding that investigations indicate the suspect acted alone and has no links to terrorist organisations or organised criminal gangs.
Earlier this week, Alzafny said police discovered an object suspected to be an IED following reports from the public at 7.08am of an explosion and scattered nails in the Desa Palma area. - December 26, 2025
