An elderly woman who stays alone in her Salt Lake apartment was made unconscious by two men who administered her an injection and robbed her valuables and cash on Saturday morning.

Police said the two men had gone to her home on the pretext of fixing the Internet connection.

Chhaya Sengupta, 71, who retired as the principal of a school in south Calcutta, has been living alone in her ground-floor apartment in Purbachal since the death of her husband last month.

A man named Subhankar Mukherjee, who was her husband’s caregiver, has been arrested in connection with the robbery, the police said. According to the investigators, he was one of the two who entered the flat on Saturday.

“Subhankar Mukherjee was recruited by the family around six months ago when Sengupta’s husband fell ill. Mukherjee worked for a few days but had an idea of where the valuables were kept,” said Sambiti Chakraborty, assistant commissioner, south, Bidhannagar Police Commissionerate.

According to Sengupta’s complaint, Mukherjee had called her up on Friday when she told him that the apartment’s Internet connection was not working.

On Saturday morning, two men wearing masks knocked on the apartment’s door. After Sengupta opened the door, they told her they had come to fix the Net connection.

“They overpowered me and pushed me down. One of them injected something into my arm and I passed out. When I came around, the two were no longer in the flat,” Sengupta said.

The gold bangles and the gold mangalsutra that she was wearing were missing.

Sengupta told the police that she found the cupboard ransacked. “Some jewellery kept in the cupboard and ₹3 lakh were also missing. I called the police. The officers came almost immediately,” said the woman.

“Subhankar Mukherjee, one of the attackers, has been arrested. We are looking for the other,” an officer in the commissionerate said.

This was not the first time an elderly Calcuttan staying alone had been attacked and robbed.

The city where a large number of elderly citizens are forced to stay alone as their children are settled abroad or live outside the state has witnessed many such attacks.

In November last year, an elderly woman who lived alone in her flat in Charu Market was attacked. Later, the family’s driver was arrested.

In September, a woman working as a caregiver to a 79-year-old woman in Salt Lake was arrested on charges of murder, 11 days after she was found dead.

CCTV footage revealed that the caregiver was in the habit of assaulting the elderly woman.