Ahmedabad: Indian Coast Guard Ship Samudra Pavak intercepted and apprehended a merchant vessel carrying approximately 1,500 kg of heroin valued at around Rs 3,500 crore off the coast of Gujarat, officials said on Sunday. "This is the largest single haul of narcotics seized till date," an official said. According to the Indian Coast Guard, based on intelligence inputs, the vessel was intercepted around 12 noon on July 29. The ship was brought to Porbandar in Gujarat on Sunday morning for further investigation. A joint investigation by the Coast Guard, Intelligence Bureau (IB), police, Customs, Navy and other agencies is currently underway, officials said.