A mobile video recorded and handed over to police by the brother of accused shows the woman identified as Chandrawathi repeatedly beating up her mother with a broom, reports said.
The video clip of the assault went viral on social media on Sunday.
"According to the complaint registered by the son, his mother was beaten because she urinated in the wrong place. There is also a family dispute for property and we are investigating the case," police officer Azad MC told NDTV.
Chandrawathi told police that it was the duty of sons to look after the mother, not that of a daughter.
Police have shifted the elderly woman to a nearby hospital.
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