Investigators found human remains in William Spengler's burned-out house, where he lived with his sister, Cheryl Spengler.
The remains are assumed to be the sister's and a medical examiner will determine the cause of death, police said.
More top news
James Shaw told of his struggle with the man who killed four people in Tennessee.
Cooler feeling into a new week
Swedish TV reported two post-mortems revealed nothing suspicious, and foul play has been ruled out in the performer’s death.