A 30-year-old mentally-challenged son beat his 57-year-old mother to death here and informed the police about his act, an officer said Wednesday.
The incident was reported on Tuesday night from south Delhi's Kalkji area.
Sameer Chaddha was detained on Tuesday night after he made a call to the police and said he had murdered his mother.
The victim, Reeta, had been staying with Sameer for a few years while her other two sons stay elsewhere.
"Sameer confessed to police that he killed his mother with a blunt object after a heated argument," Additional Commissioner of Police Ajay Chaudhary said.
Police is trying to confirm Sameer's mental status, said the officer, adding that his mother's body has been sent for post-mortem to ascertain the cause of death.