The incident took place around 7.30 AM when the woman, Ruchita (31) was on her way back home after dropping her son to school, they said.
Laxminarayan Kinkar (35), a petty contractor, allegedly stabbed her and later slit her throat, police said.
Soon after the incident, a mob gathered on the spot and handed over the man to police.
For the last two years, the victim was staying away from her husband with their 10-year-old son Manthan, they said.
