Tokyo reports Japan’s largest ever attempt at tax evasion when it learned two sisters have been stashing millions of yen in boxes to avoid inheritance taxes beginning before 2004.

Shortly before the death of their real estate investor father, Yoshiko Ishii, 55, and Hatsue Shimizu, 64, began withdrawing large amounts of their would-be shared inheritance from their father’s accounts in Osaka.

The problem for the sisters is they declared only a small fraction of this money and as a result paid only minimal tax on the hidden funds. When confronted by authorities, one sister claimed amnesia, while the other admitted guilt. Authorities claim the investigation is ongoing in Japan.