The sales tax department has lodged 47 FIRs, involving over Rs 15 crore, against steel traders for tax evasion and will register 217 more FIRs in the next few days. After all 264 FIRs are registered, it will be biggest case in Mumbai in terms of sales tax complaints at one go.

"After calculating the tax evaded in all 264 cases, we found that it's an Rs 125-crore scam," said an officer. More than 1,000 people have been booked for cheating, forgery and using fake documents. Nisar Tamboli, zonal DCP, said, "The cases are spread over five-six years. It's a huge investigation and we are in the process of filing the FIRs."

A few months ago, while going through an internal audit, the department found that hundreds of traders had not paid sales tax in the last three years and used fake documents to get the Tax Identification Number. They then approached the V P Road police station.

A team of five cops, led by inspector Sanjay Kamble, found that several firms were floated and bank accounts opened using fake documents, including electricity bills and ration cards.

The major defaulters include Asian Metal Industries, Rohan Steel Impex, Ambe Steel Center, Deep Metal Pvt Ltd.