Police have found tens of millions of yen in cash in the Saitama apartment where the wife and second son of executed Aum Shinrikyo cult founder Matsumoto Chizuo live.

Investigative sources said the Public Security Intelligence Agency tried to inspect the apartment in March this year, but the residents refused to let agents in.

The agency then filed a complaint with the Saitama prefectural police, and officers found the money when they searched the unit in April on suspicion of violating a law for regulating organizations.

Public security authorities have heightened caution against Aum’s successor group Aleph as they suspect moves to try to appoint Matsumoto's second son as its next leader.

The agency is expected to look into where the money came from.

A court ruling ordering Aleph to pay about 1 billion yen to bereaved families and victims of Aum's series of crimes has been finalized, but the group has not complied.