Arvind Pathak (38), who lost his job a year ago, committed suicide on Wednesday at his house in Mahipalpur, south Delhi.
But before killing himself, Pathak gave poison to his daughter and strangled his wife.
He left a suicide note in his diary.
Police claimed Pathak, an MBA, lost his job as a retail manager with Vishal Mega Mart in Jaipur a year ago when the company was downsized.
His wife Mamta Pathak worked as a teacher at a school in Kapashera but lost her job a few months ago.
Their daughter Abishi (11) was studying in a boarding school at Mount Abu in Rajasthan.
Pathak’s brother Akhilesh Pathak, who lives a few blocks from his house, has told the police that he was depressed because he did not have a regular income and was finding it tough to run the family.
Police said Pathak had planned ahead. “On Dussehra, Pathak called his wife who was at her parents’ house and the next day got the daughter home,” said a senior police officer on condition of anonymity.
“On Wednesday, he gave food laced with poison to her daughter and put her to sleep. After a few hours, he strangled his wife and then consumed sulphas tablets,” the official said.
Sulphas is a drying agent easily available at medical stores.
Neighbour said at 3 am on Wednesday, Pathak came out of his house asking for water.
“He was shouting for help and told us that he had consumed poison,” said Jeet Negi, a neighbour who informed the police.
“He gave the phone number of his brother and asked us to inform him. By the time he was taken to hospital, he was dead.”
Police found several strips of sulphas tablets at the house.
“He had borrowed money from his father to build the house in Mahipalpur Extension,” said the police officer.
His father who retired from the coal ministry lives in Muzaffarnagar, Bihar.