This episode features two cases that occurred 78 years apart, yet are eerily similar and both remain unsolved.  First, the tale of the Hinterkaifeck murders which occurred on March 31, 1922. Five members of the Gruber family along with their maid, Maria Baumgartner, were brutally slain with a Mattock. Before this, strange happenings began occurring on the Hinterkaifeck farm even as far back as six months before the murders. Investigators believe the murderer may have been living in the family's home up until the murders and then shortly after.  These murders remain unsolved 98 years later.

On December 31, 2000, all four members of the Miyazawa family were murdered in their home. The youngest at just six years old was strangled and the remaining members brutally stabbed. There were strange events leading up to the murders, a plethora of obvious DNA and evidence, and the murderer even remained in the home for hours after the murders.  yet these murders still remain unsolved 20 years later.  

OG Release Date: 05/25/2020

Sources:

The Scare Chamber 

Mental Floss (2017, August 31) 

All That's Interesting (2017, November 13)

Defrosting Cold Cases (2014, May 1)

Unresolved (n.d.)