The man’s wife, Anneli Auer, was first convicted and sentenced to life imprisonment for the crime before she was freed on appeal in July 2011.
The prosecutor has applied for leave to appeal that decision, with court documents outlining his belief that the crime could have been part of a satanic ritual.
Injuries on the victim’s body are cited in the additional evidence provided to the court. Prosecutors also claim that Auer often rowed with her husband, and was violent towards other members of the family.
Defence lawyer taken aback by claims
Meanwhile Auer’s lawyer Juha Manner has refuted the allegations of satanic worship and expressed surprise over the prosecution's revelations.
“The claims are baseless,” Manner told Yle.
“When there is a second trial going on behind closed doors, I cannot comment in any way on the basis of those claims (satanic worship). I can only emphasise that we should be a bit more careful about the basis for the information we give,” he added.
Auer is also on trial separately on several charges of sexual and physical abuse.