Manager Sandipan Das’s silence since returning home early on Sunday morning after being allegedly held captive for 30 hours has left police struggling to piece together the kidnap-for-ransom puzzle.

A senior police officer said on Monday that there were “grey areas” in the statements given by the family of the 34-year-old manager at Capgemini Consulting, an MNC with an office in New Town. Investigators also haven’t been able to confirm how much ransom was paid and who the kidnappers were.

“On the face of it, it was kidnapping for ransom. But the victim’s family appears to be holding back vital information that could help us crack the case, especially the identity of the alleged kidnappers,” said the senior officer.

When Metro visited the family’s Kasba home, Sandipan’s mother pleaded that she be left alone. “My husband is very ill and my son is also unwell. We are in no state to talk,” she said.

Sources close to the family alleged that the police was playing a “dubious role”, from not registering a complaint at first to pressuring Sandipan’s parents to toe their line.

Sandipan was allegedly kidnapped on Friday night after he left office earlier than usual — around 8pm — saying he was unwell. He is usually in office from 1pm till 10pm.

According to the police, Sandipan boarded a taxi and was kidnapped along the way. Another version has it that a colleague accompanied him but got off in Salt Lake’s DL block. Officials of Capgemini wouldn’t confirm whether anybody else was in the taxi with Sandipan.

The company’s vice-president and head of sales, Anish Sarkar, said that the only thing that mattered now was that Sandipan was safe.

The official version is that Sandipan’s father Samiran received a call from a kidnapper using his son’s cellphone at 9.40pm on Friday, demanding Rs 20 lakh in exchange for his freedom. The next call, also made from Sandipan’s cellphone, came around noon on Saturday. “Going by the locations of the cellphone towers, we presumed that the gang making the calls was operating from the northern fringes of the city,” an officer said.

The police had traced the first few calls to Belghoria and the Dunlop crossing in North 24-Parganas and the rest to Agarpara Station Road and Dakshineswar.

According to information available with the cops, the ransom was scaled down and fixed at something between Rs 2 and 5 lakh after the final round of negotiations with Sandipan’s family. “We were unaware of this at that point,” the officer said.

Three members of the family reached the designated spot around 1.30am on Sunday, only to receive a call from one of the kidnappers asking them to proceed to NH 2 — or Delhi Road — from where someone was to collect the money.

“They were asked to wait at a particular point, but then told to continue moving around 10 minutes later. After travelling half a km, they received a call asking them to stop. Then, a taxi stopped in front of their car. One of the alleged kidnappers emerged from the taxi and asked for the money, which was handed over,” the officer said.

Before leaving, the kidnapper assured Sandipan’s family members that he would be back home in a few hours. Sandipan, the police said, was put on a taxi at the Dunlop crossing around 4.30am. He reached home an hour later.

According to his profile on LinkedIn, a professional networking site, Sandipan had previously worked as a team leader at Infosys BPO and ACS, as an accounts assistant at Accenture Services and a senior executive at PricewaterhouseCoopers.