It was a midnight call her partner Suraj Sinha had made from his mobile phone that sowed the seeds of Anuradha Mangatri's suicide.

This was revealed by police after interrogating Suraj, 25-year-old son of Bihar Assembly's chief marshal Bhanu Pratap Sinha. Suraj was arrested on Sunday on the charge of abetting the suicide of 28-year-old Anuradha, a private bank employee with whom he lived.

'Anuradha came to know about the other woman about three-and-a-half months ago. She caught him red-handed while he was talking to the girl over his mobile phone around midnight,' said an officer working on the case.

Anuradha was found hanging around 6.30 am on Saturday at her South Road residence, in the East Jadavpur police station area, where she lived with Suraj.

A software firm employee, Suraj found her body on his return from office in Salt Lake Sector V. Police found a suicide note, in which Anuradha had mentioned the name of the other woman, a colleague of Suraj's, and blamed him for her decision to kill herself.

Suraj was produced on Monday before sub-divisional judicial magistrate Manjit Singh and remanded in judicial custody.

Police did not pray for taking him in custody, saying they had evidence enough to prove Suraj's abetment of Anuradha's suicide.

Elaborating on the midnight call, an officer said: 'Suraj thought Anuradha had fallen asleep and went to another room. He rang up the other woman. Anuradha caught him in the act. Suraj tried to fob her off, saying he was talking to a colleague on night shift.'

Next morning, when Suraj was bathing, Anuradha went through the call details of the mobile phone and discovered that the midnight call had been made to the other woman. 'Suraj claimed he had only discussed office work,' said the officer.

Police came to know Anuradha and Suraj had met each other more than three years ago at a Camac Street call centre, where they used to work.

'A year ago, Suraj left the job and joined the software firm at Saltlec, ' disclosed H.K. Kusumakar, additional superintendent of police (industrial).