A couple returning home after shopping were attacked and left wounded by a 30-year-old neighbour.
The incident took place at Anandanagar in Thakurpukur on the southwestern fringes of Kolkata on Sunday night.
Police have arrested Sanju Saha for the alleged attack.
Amit and Sima Dinda were at the trauma care unit of SSKM Hospital on Monday evening. Doctors said their condition was critical. The husband and wife have suffered significant blood loss from the injuries.
A section of residents claimed that Saha was mentally unstable and had attacked a few others in the past with bamboo sticks.
This was the first time when he picked up a deadly weapon.
The police said Saha could not provide any plausible reason for the attack except that he suddenly ‘lost his cool’ on spotting the two walking down.
Eyewitnesses said Saha attacked the couple around 9.30pm on Sunday when they were walking home.
He picked up a chopper from a meat shop in the market and attacked Amit even before anyone who was around could understand what was happening.
“When Sima tried to intervene, she too was attacked. By then her husband had already been injured with the sharp weapon on the shoulder,” said a senior officer of Thakurpukur police station.
When the crowd around in the market tried to stop the chopper-yielding Saha, he chased a few brandishing the weapon.
“Sanju (Saha) kept threatening that ‘I have already attacked two and anyone who came in my way will face a similar attack’,” said Mihir Paramanik, one of the eyewitnesses.
“We had to step away till he walked into his house.”
Some of the local residents and bystanders informed the local police and arranged for shifting the injured couple to a hospital in Thakurpukur.
“A few of Saha’s neighbours, who were aware of the attack, stepped out of their homes and locked his house from outside before informing us,” the police officer said.
“When we reached there were blood stains on his hands and fingers,” he added.