Investigators probing the murder of a bank manager’s wife, at an apartment in Thakurpukur on July 31, claim to have found an Ulfa link in the plot.

Officials, on their return to the city from Assam, said the Ulfa angle was among the strongest emerging from a week-long probe at Dhuliajan, where United Bank of India (UBI) manager Jayanta Banerjee had been posted for over three years.

“Banerjee had antagonised an Ulfa activist while he was posted there,” an official involved with the probe said. According to the report sent by investigators from Assam, Banerjee had refused to grant a bank loan in favour of a travel agent. The agent, who happened to be the brother of an Ulfa activist, threatened Banerjee that he would have to pay with his life for the refusal. “He used to receive threats regularly during his tenure there,” revealed the official.

Around 3.30 pm on July 31, an unidentified man in his twenties rang the bell of Banerjee’s third-floor flat. Banerjee had just been transferred back to Calcutta and was at home with wife Sarbari and daughter Sohini.

When Sarbari opened the door, the youth at the door attacked her with a knife. Alerted by her cries, Banerjee rushed out to her rescue. The assailant turned on him, slashing him across the stomach. When a bleeding Sarbari tried to pick up a shoe-rack to hit back, the assailant stabbed her a second time, officials said, adding that this strike later proved fatal.

Daughter Sohini was asleep in the bedroom when the attack took place. The injured couple chased the killer till the landing on the second floor, before collapsing, Thakurpukur police station officers added.

Sleuths of the Criminal Investigation Department (CID), who are also “studying the case to understand its merit”, have stressed the Ulfa line, too. “The agent, after being denied, apparently urged his brother to teach Banerjee a lesson,” said a CID officer. “The Ulfa activist then took up the matter with the UBI manager. Banerjee, too, admitted to these details during interrogation by the CID,” officials said.

Sleuths, however, refused to disclose the name of the travel agent or his brother, as that would hamper the probe.

A pen-sketch of the assassin — based on the description provided by Banerjee — shows a well-built youth, around five-and-a-half-feet tall, with a blunt nose, a square jaw and curly hair.

There is speculation over the killer weapon, left behind by the assailant. “It is the only clue that we have right now. The knife appears to be a single piece from a set of knives,” said an officer of Thakurpukur police station.