Northeast district police chief Mior Faridalathrash Wahid said the boy was now under the protective custody of the police and the Welfare Department.
In a statement, he said the boy’s father, in his 40s, had been identified but yet to be detained for questioning. He is believed to be a school bus driver.
“We will investigate the father for ill-treatment, neglect, abandonment and exposure under the Child Act 2001,” he said.
Photos of the naked boy went viral on Facebook on Saturday, after residents spotted him sitting by the stairwell in a puddle of his own urine.
Paya Terubong Village Security and Development Committee Chairman Frankie Kee said the boy was chained to his left ankle for five hours on Saturday. He was let go at 3am.
Kee also said the boy’s father had threatened to hurt anyone who helped free the boy.
The father apparently resorted to this punishment because the boy was naughty.