Prime Minister Yukio Hatoyama remained mum Tuesday on his ever-widening fundraising scandal, saying he trusts prosecutors to judge whether he is liable for any misconduct.

Prosecutors are reportedly preparing to file charges against a former Hatoyama aide for violating the Political Funds Control Law, including faking the sources of donations made to Hatoyama between 2005 and 2008.

Dismissed after the scandal broke over Hatoyama's fund management body's logging of fictitious donors, the former government-paid aide may be indicted without arrest, sources said.