Sanader, who is held in extradition custody in Salzburg, was questioned for about an hour via video conference.
In his brief statement Sanader denied his involvement in money laundering, Koenig said, explaining that Sanader was suspected of money laundering, but no charges had been formally brought against him.
Sanader asked for an additional hearing, which will be held in January.
The investigation in money laundering implicated one member of Sanader's family and a third person, but Koenig declined to reveal their identities. The probe was launched after a Tyrolean bank reported a money laundering case implicating the former Croatian premier.
Sanader was arrested in Salzburg on 10 December following a warrant issued by Croatia. He has been in custody since.