The Central Bureau of Investigation on Wednesday said that it had written to businessman Nirav Modi, who is one of the primary accused in the Punjab National Bank fraud case, on his official e-mail address, asking him to return to India and cooperate with the investigators, ANI reported. But Modi wrote back saying he cannot as he has a business to take care of outside India.

The investigating agency replied to Modi’s e-mail and told him that it was mandatory for him to appear before the investigators by next week. The agency added that the Indian High Commission in the country he is currently in would make his travel arrangements.

The Punjab National Bank had informed the Bombay Stock Exchange on February 14 that it had detected “fraudulent and unauthorised transactions” at its Brady House branch in Mumbai. The amount of fraudulent transactions could be Rs 12,703 crore, about Rs 1,323 crore more than the initial estimate of Rs 11,380 crore.

A few officials at the public sector bank had reportedly issued fraudulent Letters of Undertaking – essentially letters of credit telling others banks that it would meet a customer’s liabilities – to Nirav Modi’s companies.