Calcutta, July 19: The murder of six members of the Saha family was not carried out in the manner originally presumed — an act of poisoning by a debt-ridden man who later hanged himself.

On Saturday night, Shibendu Saha killed his parents, his wife and two children and his brother before taking his own life in their south Calcutta home on Tollygunge Road.

Post-mortem of the bodies late on Sunday night revealed an array of disconcerting truths. Anubha and Simanta — Shibendu’s mother and his three-year-old son — were poisoned. Shibendu’s younger son, three-month-old Bedanta, appears to have died after being hit on the top of his tiny head. His wife Swati was poisoned and then strangled.

The seniormost member of the family, Shibendu’s father Nabendu, and his brother Krishnendu were poisoned and bludgeoned on the backs of their heads with a blunt object.

“Even if there are no external injury marks or even blood, a post-mortem would reveal if a victim has been hit by an object. In some of the cases, these signs were clearly present, besides the presence of poison in the blood,” said a senior officer of the detective department.

Preliminary investigation and post-mortem reports suggest Shibendu took time to execute this elaborate devilish plan. Only after he was sure his mother and his elder son were dead did he proceed to conduct the next round of killings.

The entire act of murder, police said, was spread over two-and-a-half hours — between 12.30 am and 3 am. He hanged himself several hours later, taking the extra precaution of tying his legs with a towel.

Before that, Shibendu sent an SMS to sister Jayashree telling her to go through the suicide note he was leaving behind. The cellphone message was sent around 6.15 am.

On the basis of the note, where Shibendu narrates the family’s financial difficulties, the police late last night arrested his uncle Amalendu and his wife Anita.

The two live in the same house on a different floor. Amalendu was a partner in the family’s business in wholesale supply of flour and semolina and making bakery products.

Amalendu and Anita were produced in court today and remanded in police custody till July 27.

In the note, Shibendu said he got sucked into a cycle of borrowings because of business trouble, for which he blamed Amalendu. “I have lost everything,” Shibendu wrote, in trying to rescue the business.

He suggested a conspiracy between Amalendu and Anita, whom he referred to as a “snake”, to siphon off money from the business.

“To argue that a debt trap was the immediate compulsion is hard to accept. The loan amount was not astronomical — it was a few lakhs and could have been organised, given the assets available with the Sahas,” said an investigating officer.

While the chemical reports are still to come in, investigators said mercuric chloride was possibly used as the poison.

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