The seized ivory cache that was valued at Rs 12 crore.

After an illegal trade in ivory for 25 years, Delhi businessman Umesh Aggrawal was arrested on Sunday, sources told NDTV; 480 kgs of ivory, for which at least 18 elephants from Kerala had been killed, were seized from his house.The seized ivory - valued at Rs 12 crore -- has been sourced from various states, said Surendra Kumar, the Additional Principal Forests Conservator, Vigilance. Much of this ivory has also been acquired from captive elephants -- by pruning their tusks - which is also illegal, officials said.The arrest took place after an operation of 4 months, sources said. "Operation Shikar" was a multi-department operation involving the Kerala Forest Department, Wildlife Crime Control Bureau and the Delhi Police.Mr Agrawal is believed to be the kingpin of the ivory trading syndicate in India. Officials who interrogated him said at various art exhibitions, he would display fake ivory items to attract customers for the genuine items.The tip-off about this enormous racket came from a cook working with the Kerala Forest Department, sources said."Cumulatively, 550 kg of ivory was seized from Thiruvanathapuram and Delhi," said Mr Kumar. Besides Aggrawal, 50 people arrested till now, 6 vehicles and 20 guns confiscated. "We are now aiming at nabbing the end purchasers. They are big names and we are collecting evidence against them. We hope to get help from Central Bureau of Investigation in this."Kerala has four elephant reserves - Wayanad, Periyar, Nilambur and Anamudi. The state's wild elephant population is around 7000. But poaching is also rampant. Reports say around 40 elephants have been killed in the last two years.