The attack unfolded at a hotel in Nalasopara on Monday night, when Dharmendra Vishwakarma was summoned by a man named Arjun Dubey.
Hemlata Singh, the corporator for ward 18, joined by associates Amrish and an unnamed aide, confronted Vishwakarma, pushing him, slapping him, and striking him with bamboo sticks.
Police filed an FIR and a cross‑FIR at Tulinj station, and later detained Vishwakarma and associate Manish Singh.
Singh and Amrish remain at large as authorities intensify the search.
The incident comes amid a series of violent episodes involving Shiv Sena members, including last month’s assault on hospital staff and the arrest of city chief Rahul Gharat.
Vishwakarma, who works as a farmer, said the assault has left him deeply shaken and fearful of further attacks.