The 26-year-old accused left his wife in a pool of blood and fled after locking his house on Monday, they said.
According to police, the incident came to light on Tuesday when the couple's landlord called up police and informed about the two quarelling the previous night.
When the police team reached there, they found the woman lying in a pool of blood.
The accused, a resident of Bulandshahr in Uttar Pradesh, was arrested yesterday from near Nangloi railway station in west Delhi, he said.
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During interrogation, he confessed to the crime and disclosed the sequence of events, police claimed.
The woman was sister-in-law of the accused's elder brother. The two had fallen in love and married about a year ago and before coming to Delhi.