A senior police officer said Suvankar Ghosh was thrashed by locals after he barged into the beauty parlour run by the 23-year-old woman and following an altercation he allegedly tried to slit her throat.
As the woman managed to escape with gashes on her throat, people in the neighbourhood rushed to her aid and caught hold of the youth.
He was thrashed by a section of the crowd and declared dead at local hospital, the officer said, adding, the knife was seized by the police.
The woman's family members claimed that she had been avoiding Suvankar for past several months after he proposed to her. The youth had also attempted to speak to her in public places on several occasions.
Suvankar's family, however, blamed the girl's guardians as having conspired to kill the youth and claimed that they were in a relationship previously.