Shameem and Manoj were arrested recently for the murder of Padam Singh, a native of Nepal, at his house in Sarai Kale Khan in east Delhi, police said.
Singh was living with his wife Tara Devi and younger son Sonu in his house.
A small clue came into light that Sonu had picked up a small quarrel with three boys namely Shameem, Manoj and Aneesh last week and they could not be located after the murder.
On a specific tip-off, police arrested Shammem and during interrogation, he said Sonu had picked up a quarrel with his younger brother Aneesh.
They reached Sonu's house and found his father sleeping on the ground.
"They decided to kill his father. All the three overpowered Singh and murdered him," a senior police official said.
Efforts are being made to arrest Aneesh.