SACRAMENTO -- A young mother abducted, beaten, branded and then left on the side of I-5.
Sherri Papini's unique and disturbing kidnapping case is still under investigation.
"It's clear that this is a legitimate case of abduction, and the other scenarios that people have talked about are improbable," said Private Investigator Cody Salfen.
During the three weeks the mother of two was missing, her family hired Salfen to work alongside law enforcement.
Salfen says there are many things that make this case unique.
"The fact that she was recovered alive such a long period of time after her initial disappearance, that really defies my experience with abduction cases," said Salfen.
Another unusual factor is that Papini says her kidnappers were two women.
"When you have a criminal duo, essentially, or a pair of people, traditionally that would involve a male or a female. In most criminal duo relationships or situations you'll have the male dominant role and the more subservient female role," said Salfen.
The Shasta County sheriff says Papini was branded; potentially a way for the alleged kidnappers to exert power over her and create fear, said Salfen.
FOX40 asked him if he has any idea what the motive might be.
"I really don't at this point, it's so difficult to try to comprehend what's going on," said Salfen.
With Papini home recovering from her traumatic experience, there's still a long way to go until investigators figure out who took her during a jog near her Redding home and why.