Weekly magazines Der Spiegel and Focus both report that the exact time of death has yet to be determined, but that the traces of DNA found on Bögerl's body could be helpful.
Investigators have already said the man who called to demand money from Bögerl's husband, a local banker, was local, with a strong regional accent.
The 54-year-old woman was kidnapped from her home on May 12. A subsequent attempt to hand over €300,000 failed, and her body was found not far from the hand-over spot, on June 3.
Der Spiegel said that the DNA traces recovered from her body were, however, of poor quality and could make comparisons difficult to make.