Financial regulators have already launched a probe into AIJ, but a criminal investigation suggests that police or prosecutor may seek to arrest managers involved in the growing scandal. The newspaper did not say where it obtained the information. Separately, the Nikkei business daily said that Japan's Financial Services Agency plans to seek stricter oversight of investment advisory firms in the wake of AIJ's losses. New proposed rules include forcing companies to disclose historical returns, investment targets and any ties with brokerages, the paper said. The FSA has already asked 265 advisory firms to fill out a questionnaire and will conduct further inspections on a select group of firms based on their responses. Unlike banks and brokerages, investment advisory firms are not regularly inspected by regulators and their filings are not so closely scrutinised, raising concerns about the safety of the pension money they manage.