Prosecuting lawyers on Wednesday appealed a lower court acquittal of Japanese political power broker Ichiro Ozawa in a funding scandal.
The appeal prolongs the veteran lawmaker's status as criminal defendant for months, if not years.
The Tokyo District Court last month found 69-year-old Ozawa not guilty of violating political funding law related to a 2004 land deal. The court said he must have overseen false accounting by his former aides, but there was no evidence to prove his collusion or awareness they were illegal.
Chief prosecution lawyer Shunzo Omuro said it was "illogical" to rule out Ozawa's collusion with the aides while acknowledging his oversight of their actions.
The prosecuting lawyers had demanded a three-year prison term for Ozawa, alleging he was fully aware of false bookkeeping by the three aides. They said Ozawa authorized the false entry of the transaction in an annual political funds report to the government.
Ozawa repeatedly told the court that he had no knowledge of his aides' actions and has never checked bookkeeping.
"It would be impossible to overturn the acquittal," Ozawa said in a statement. He said he had "trouble understanding" the appeal.
Ozawa engineered the Democratic Party of Japan's 2009 rise to power. The scandal has damaged his chances of becoming prime minister, though he remains influential behind the scenes. Despite his negative image as an old-style, wheeling-and-dealing "shadow shogun," he still has a loyal core of supporters.
Ruling executives on Tuesday decided to reinstate his party membership, effective Thursday. The step would allow him greater influence over the key party policies, including a proposed sales tax increase, which he opposes.
The three aides, who were tried as a group, were given suspended prison terms of up to three years for failing to register a 400 million yen ($5 million) loan from Ozawa to his funding body in the Tokyo land deal and for accepting 100 million yen ($1.3 million) in illegal donations from a construction company.
Ozawa has criticized his prosecution as a politically motivated abuse of state power.