I would bet that the children/siblings/parents of Chad/Lori/AC know if the dog and cat that were by the body were theirs... or not.. or perhaps background on such that were found near the grave that didn't need the anthropologist to identify.
Supposedly, the three signs and triad iirc of a serial killer are
1)wetting the bed (as a child, so as an adult, only siblings/parents or friends when young would know) MOO
2)fires/arson
3)hurting animals
Just looked it up.. there are mannnnnnnnnnnny links to such triad and we have discussed this in many cases here at WS MOO
"The Macdonald triad refers to the idea that there are three signs that can indicate whether someone will grow up to be a serial killer or other kind of violent criminal: being cruel or abusive to animals, especially pets. setting fire to objects or otherwise committing minor acts of arson. regularly wetting the bed.Mar 24, 2020"
The Macdonald Triad: Can 3 Behaviors Predict a Serial Killer?
And then there's Chad mentioning in his memoir how he enjoyed killing bees as a child iirc