busted in the Adityapur Industrial Estate under Adityapur police station in Seraikela-Kharswan district, DIG (Kolkhan) Md Nehal said here.
The raiding police team recovered 102 pieces almost finished fire-arms and fire-arm making equipment from Vijaya Laxmi Enterprises located in the VII phase of the Adityapur Industrial Estate.
Addressing a press conference, Nehal said four persons including three from Bihar were arrested.
The four who had criminal antecedent, were operating the illegal fire-arms business for the past six months, the DIG said.
He did not rule out of the possibility of some arms manufactured in the unit being sold to extremists and criminal groups.
The police were investigating whether the gang had any link in Kolkata, from where they used to procure raw-materials for making fire-arms.
The gang's marketing network was also being investigated, the DIG said.