Aarnio's son is suspected of tax evasion because a plot bought by Aarnio was put in his son's name.
The former police boss said that he did not in any way discuss with his son that the plot would be a gift.
According to Aarnio, the plot was loaned to his son and the idea was that he will pay back for the plot.
His son told the court that he did not remember why the plot had to be in his name, and that not at any stage had there been a conversation about the plot being a gift.
Aarnio has been in detention since November 2013.
