A 20-month-old boy was brought out to buy diapers at midnight on Wednesday but barely 12 hours later, turned up dead some 250km away.
District police chief Assistant Commissioner Amiruddin Jamaluddin said a 35-year-old suspect had been arrested over the death, which has been classified as murder.
He said toddler Law Hong Jun's 24-year-old mother and her boyfriend were staying in Taman Seri Watan and had brought the child to Batu Pahat, Johor last week.
"About midnight on Wednesday, the man told the victim's mother that he was going out to buy diapers and took Hong Jun with him," he said.
He, however, did not return and the anxious mother, a Thai, received a phone call 12 hours later from Ampang Hospital informing her that her son was dead.
Shocked and in disbelief, she rushed back to the capital and headed straight to the hospital, where the news was confirmed.
Amiruddin said the man had gone to the hospital yesterday morning claiming Hong Jun was unconscious but doctors who examined the victim pronounced him dead.
It is understood that the victim had been dead for about two hours and had scald marks on his body.
The police were immediately alerted by doctors and an autopsy was carried out to ascertain the cause of death.
The mother, who was seen waiting at the mortuary, declined to speak to reporters.
Amiruddin said police were interrogating the unemployed suspect, to determine the circumstances which had led to the baby's death.
It was learnt that the suspect was in a relationship with the victim's mother, and was not the biological father.
This is the second such case within a week. Aa Myanmar man was arrested by police on April 13 in Ampang over the murder of a two-year-old boy who died of internal bleeding.
The victim's 24-year-old mother had taken the unconscious toddler to Ampang Hospital on April 12 where he was pronounced dead on arrival.
The 28-year-old suspect, the victim's stepfather, was detained as doctors discovered bruises on the victims cheeks and private parts.
Last month, a 4-year-old boy was rescued from his father and stepmother after a babysitter discovered bruises on his body and reported the incident.
The boy was found to have injuries to his right brow, bruises on his right cheek, scratches under the chin and old bruises to the back of the head and face.
The case came to light when the babysitter called the Talian Nur on April 16 after she saw the extent of the injuries.
The following day, police went to the parents' home in Jalan Duta and arrested his 33-year-old father. His stepmother, however has not been located.
The boy later told Welfare Department officials that both his father, a sales executive, and stepmother had abused him.
