The tragic incident has occurred in Panrui in Birbhum district of West Bengal where supporters of the ruling Trinamool Congress (TMC) and BJP clashed in recent times.
The policemen allegedly rubbed nettle leaves into the woman's private parts and also slit various parts of her body with blade.
On Wednesday, a BJP supporter named Sheikh Mithun was injured in the clash in Sattore near Panrui and he took shelter at the residence of his aunt's father in Burdwan.
On Saturday, the police arrived at their house in search of Mithun but not finding him, they took his aunt to the nearby bushes and allegedly tortured her.
The woman alleged that the police took her to the Ilambazar Police Station in the night and she was brought back home by her kin. The family claimed that the police tortured the woman for supporting the BJP. The woman was admitted to Suri Hospital in serious condition.
The district police officials reportedly refused to remark on the issue.