A 17-year-old schoolgirl, the youngest of three sisters, purportedly hanged herself at her home in East Burdwan district on Wednesday evening following month-long threats and mental torture allegedly by people close to a Trinamul leader who won civic polls.

The death has sparked off a series of protests with family members alleging the minor was forced to commit suicide after supporters of victorious Trinamul candidate had hurled bombs in front of their house and threatened to rape the three sisters on Wednesday evening.

The deceased girl’s sister said threats and mental torture by the candidate’s sidekicks had become intolerable after he had won the polls.

Police have arrested four persons and started a case abetment to suicide against them. “We have arrested four persons and started a case according to the complaint filed by the family. The probe is on to find out the abettors behind the death,” said Kamanasish Sen, the East Burdwan police chief.

Despite the arrests, family members of the girl did not feel relieved. They said they had been under tremendous threats since the accused had been nominated to contest the election. The torture on them started as they were aligned to his rival camp in Trinamul.

A wall graffiti painted allegedly by the elected councillors’ men on the wall opposite the deceased minor’s house portrayed three young girls hanging from a tree with their hands tied to one of its branches.

“The continuous threats led my sister to go into depression and she used to worry about their fate if the candidate won the poll. After his victory, people close to him came and molested us. My sister could not bear it and hanged herself,” she added.

Trinamul, however, rejected the charge of the party’s involvement in the incident. Rabindranath Chatterjee, the East Burdwan district president of Trinamul, said action would be taken against the councillor if he was found guilty.

The accused councillor said: “It is the fallout of a family dispute and I am in no way connected with it. Let police investigate and the truth will come out.”

Trinamul MLA Khokan Das said the law would take its own course. “As far as I know, the party has no connection with the incident. The police will investigate and take action against the guilty.”

Local residents blocked the road demanding the arrests of all those responsible for the girl’s death.