Speaking to reporters here, Deputy Inspector General of Police K Jagadeesan said police questioned one Etheine (54), a Public Works Department employee, as they suspected that only those close to the family could have committed the crime.
Etheine reportedly confessed to having committed the crime and was arrested from his residence, the DGP said, adding he was later remanded to judicial custody.
The DGP said Ethiene had visited the house of Honurine (68), on February 15 night and allegedly quarrelled with herover a financial transaction, police said.
Honurine had been staying in Puducherry for the last 20 years while her two adopted children were residing in France.
Her estranged husband is also away in France.