Top executives of Japanese conglomerate Toshiba were systematically involved in overstating more than $1.2 billion in profits, the firm's independent panel has warned in a report to be released on yesterday, according to local media. The firm has hired an outside team of investigators to look into its accounting irregularities, which were unveiled after the nation's securities watchdog probed its balance sheet earlier this year.The accounting irregularities are believed to have affected its mainstay infrastructure-related, semiconductor, television and personal computer businesses. Toshiba, which makes various products from batteries to nuclear reactors, has already admitted that some of its businesses would need to go under the microscope, although the extent of the problems - and who is responsible - remains unclear. But public broadcaster NHK, quoting unnamed sources, said the panel had concluded that the firm had committed "organized wrongdoings" over the scandal with the involvement of its top managers. The panel is expected to warn that the firm needs to downgrade its operating profit by more than 150 billion yen ($1.2 billion) over the five years to March. Toshiba President Hisao Tanaka is expected to resign over the scandal on Tuesday.