Rs 20-30 crore spread over 400 people! That's kind of extremely huge transactions. I hope he was not actually involved in money laundering. The average user's transaction comes down to Rs 750,000. I don't think transactions like these will get ignored by banks in India.
What i think they did was look at his btc address saw the total transaction and then calculated it with the highest point btc was at. he did have over 1000 btc when he started 1.5 years back