A 33-year-old hanged himself after killing his mother and grandmother at his home in Andheri in Mumbai on Wednesday, said police.
The police said Samir Baraskar was going through financial crisis.
The incident took place between 12.30am and 4am.
Baraskar smothered his grandmother, Fatima, 65, with a pillow, strangled his mother, Minatai, 55, with a belt and then hanged himself from the ceiling, said police.
No suicide note was found at the spot.
Baraskar ran a vada pav and tea stall at Jeevan nagar in Andheri (West).
The bodies have been sent to Cooper hospital for post-mortem.
A case of murder has been filed under section 302 of the Indian Penal Code.
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