The National Bureau of Investigation received Vanhanen's final testimony, and the matter has moved to the State Prosecutor.
The Parliament's Constitutional Law Committee will consider the case next Tuesday.
The investigation is looking into whether Vanhanen should have recused himself from the decision to grant financial support from the state-run Slot Machine Association (RAY) to the Youth Foundation (Nuorisosäätiö) -- a non-profit housing group that donated 23,000 euros to his presidential campaign. Vanhanen is a former chair of the Foundation.
The government granted more than a million euros to the Youth Foundation between 2006 and 2009. As an MP and government minister, Vanhanen voted several times on funding for RAY. He stepped down as PM and Centre Party chair in June and left Parliament in September.
The final decision on any possible charges is up to the Parliament.
