Pathak's mother, Subha, was arrested on murder charges. Earlier, Subha and her husband Dharmesh were detained for questioning after the post mortem report indicated that Nirupama's death was caused by asphyxia as a result of smothering, SP Kranti Kumar said.
"We have arrested her under Section 302 (murder), 201 (causing disappearance of evidence) and 120 b (criminal conspiracy) of IPC based on circumstantial evidence," Kumar said.
Asked whether it was a case of honour killing, the SP said, "The matter is under investigation."
According to the post mortem report there was a ligature mark around her neck pointing to strangulation with a rope.
He said the police were misled by the family who had said Nirupama died of electrocution on April 29.
The police were also investigating whether her father, who was a bank employee in Uttar Pradesh's Gonda district, was at home at the time of the incident.
The parents of the 22-year-old journalist were reportedly opposed to her marrying Priyabhanshu Ranjan, her batch mate at IIMC, who belongs to another caste.
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