In Basti's Tahir village, 45-year-old teacher Sudha Yadav lost her life after a violent clash on Tuesday.
The incident involved Lakshmi Yadav, a local Congress women's wing president, and her relatives.
What started as an argument quickly escalated, leaving Sudha fatally injured.
She died around 1pm at the hospital.
Lakshmi Yadav detained for questioning
This wasn't a sudden fight. The two families had been at odds for years over claims that Sudha faked documents to get her job (a court dismissed this long ago).
On Tuesday morning, Lakshmi allegedly threatened Sudha and called others armed with sticks and knives.
The attack also left Sudha's husband and children hurt.
Police have now detained Lakshmi and others for questioning as the investigation continues.