Our investigation is on and we are hoping to get vital clues after the interrogation,' he said.

NCB sources said that Milstein, who was in his mid-50s, was a resident of Montreal city and had come to India on a vacation.

He was returning to New Delhi from Kullu-Manali in Himachal Pradesh in a car, which he was driving himself. He was expected to board a flight back to Canada in a couple of days.

Kullu Valley is known for illegal cultivation of opium and high-quality charas. The Malana cream variety from the valley is considered one of the best in the international drug market.

In February this year, Chandigarh's Alliance Francaise former director Isabelle Normand was also arrested with charas in Kullu, following which she was deported to France.