RIVER FALLS, WI (WTAQ) - A judge told Aaron Schaffhausen that he has until December 14th to decide if he wants to plead insanity to the killings of his three daughters in River Falls.

Circuit Judge Howard Cameron also gave Schaffhausen’s lawyer until December 28th to ask for a change of venue – in which a possible trial would either be moved, or have a jury brought in from outside the area.

Assistant state attorney general Gary Freyberg told the judge that he believes the 35-year-old Schaffhausen killed his daughters in order to hurt his wife, whom he divorced back in January.

It’s the first time any hint of a motive was made public – and Freyberg wouldn’t say anything else about it.

He did say, however, that Schaffhausen could use certain evidence in the case to hurt his ex-wife Jessica – and that’s why the state asked Judge Cameron Friday to expand an order that prohibits the release of certain evidence, like crime scene photos.

There was no immediate ruling on that request.

Schaffhausen’s next court appearance is on December third.

Afour-week trial is scheduled for April in Saint Croix County on allegations that he killed his daughters last July at the River Falls home where their mother lived, after she allowed him to see the children alone.