Sahil's body was discovered by a neighbour on the first floor of the building, which also housed a temple, in Gokalpuri in east Delhi, police said.
The boy had gone missing Saturday evening. His mother Sana Khan had lodged a complaint with police.
A strangulation mark was seen on the neck of the body and there were blood stains around the mouth. "It seems the boy was killed and the body stuffed inside the cooler," said a police officer.
Sahil lived with his mother in Gokalpuri. His tailor father Javed lived separately. The father said he suspected his wife was involved in the killing.
Police said a person known to Sahil's mother had been detained.
--IANS (Posted on 02-09-2013)