Three siblings drank carbolic acid in an apparent suicide bid in their home in West Burdwan’s Hirapur on Thursday after losing their mother less than a day before.

The eldest sister reportedly survived but remains critically ill and admitted at Asansol district hospital, while doctors at the same hospital, where the mother perished, pronounced two brothers dead on Thursday.

Police said they received information that four persons of a family had died under suspicious circumstances at an IISCO Steel Plant quarters in Burnpur.

“We rushed to the spot and found all four members of the family lying unconscious. One of them, a woman, was gasping for breath. We rushed them to hospital where doctors declared three of them dead. The lady was admitted to the hospital,” said Abhishek Modi, deputy commissioner of police (west).

He said the police had recovered a suicide note from the room. “As of now, we suspect that it was a case of suicide. We have found a hand-written suicide note and empty bottles of carbolic acid from the room where the bodies were laying. We are verifying it,” said Modi.

The police said the suicide note stated that nobody was responsible for the subsequent death and the suicide was owing to grief over the death of their mother to illness.

The deceased were identified as Jayanta Kar, 58, his brother Biplab Kar, 54, and their mother Geeta Kar, 83.

Jayanta and Biplab’s sister Maya Kar, 52, remains critically ill and admitted to the hospital. Jayanta was a worker at the steel plant and all of them used to live at the company quarters.

All bodies have been sent for postmortem.

The police and neighbours said the siblings were unmarried and had been taking care of their ailing mother for several years. “They did not marry because of that. I know Jayanta. He used to tell us that they would not live if their mother died. They were very much devoted to their mother,” said Purnendu Mukherjee, a local Trinamul Congress leader.

In a separate incident, Urmimala Barnawal, 50, apparently committed suicide by consuming pesticide at the Sonar Tari Abashan, a government-housing estate for the poor, on Wednesday night. The police said she committed suicide because of an ongoing family feud and attendant mental depression.