A four-month-old baby boy choked to death on his milk at the house of a baby-sitter in Taman Impian Ria, Machang Bubuk, here on Wednesday, police announced on Thursday.

Muhammad Hakimi Mohd Arsyad was rushed by the baby-sitter to the 1Malaysia Clinic in Alma when he was found to be motionless in his cot after his mother, factory worker Rohaya Abdul Raza, 31, had sent him there at 6.30 am, said Penang CID chief SAC Mazlan Kesah.

The baby-sitter related what had happened to the boy's father, security guard Mohd Arsyad Ahmad, 27, at 10.35 am, he said.

"A post mortem at the Seberang Jaya Hospital found that the baby had choked on his milk," he said.

Rohaya said she would wait for a report from the hospital and make a police report to prompt an investigation.