I had not previously read about this case, so I've spent some time reading through the thread and some articles. I can envision several possible scenarios:
1. One of the babysitters killed Arianna in a fit of rage, reminiscent of Kyrian Knox's murder, only in this case when the mother kept insisting on seeing her daughter, the mother is murdered. But, it seems like they studied Caylee's murder and took some pointers from Casey (e.g., claiming they took Arianna to Disneyland).
Nicole was reportedly on her way to meet with "the babysitter." She never returned, but a message was sent from her phone to her roommate at 12:45 a.m.:
"She was like 'I have to meet my babysitter. She's over at some restaurant on Third Street. She's upset, I need to go see if she's OK,'" said Goyette Williams. "She said she was only going to be gone for five minutes."
But Nicole isn't back in five minutes.
"I got a text message at 12:45 in the morning saying she was on her way to Fresno with somebody named 'Sam,' who she has never mentioned before, and I'm like 'Who is Sam? How are you getting to Fresno?'" said Goyette.
<snip>
https://crimewatchdaily.com/2017/03...-hold-key-to-mothers-murder-in-san-francisco/
Someone wanted Nicole placed in Fresno to divert suspicions, and hoping to delay (even avoid) the discovery of her body. If Arianna died accidentally while in the care of the babysitters, why would the babysitters lie and allow that lie to escalate to murder? By attempting to cover an accidental death with a murder, the perps would be increasing their risk of detection and the length of their confinement when detected. Not an accident, IMO.
2.
Police served search warrants at the Hearne family residences in Emeryville and Oakland, as well as a third home in Daley City. It's been reported there was no sign of the 2-year-old anywhere.
[...]
There was no answer at Ciolo's last-known address in Daley City, nor at Helena's last-known address in Oakland. Neighbors said Helena, her husband and kids were long gone.
<snip>
https://crimewatchdaily.com/2017/03...-hold-key-to-mothers-murder-in-san-francisco/
I hope LE did a thorough search of the homes, including the use of cadaver dogs and luminol. If so, it's possible HH and her husband really did keep Arianna for their own child and took her with them when they moved to an undisclosed location. Why they would do so and murder Arianna's mother in order to keep her, seems very bold, creating the same problems as allowing an accidental death to escalate to a murder.
3.
Fitts had been homeless at one stage. That's when she met Lemasani Briggs, a self-described "street pastor" and Evangelist from Daly City. Briggs is a person of interest in the case, according to San Francisco police.
"My thing is that I help people," said Briggs.
[...]
Fitts friends say Briggs niece or some relative of hers used to frequently babysit Arianna in Oakland. They say Fitts was growing increasingly frustrated because the babysitter refused to let her see her daughter in the weeks leading up to her death.
<snip>
http://www.ktvu.com/news/121832978-story
Besides Arianna meeting a violent death at the hands of her babysitters, another strong possibility, offering hope Arianna is still alive, involves a bogus adoption agency. I remember seeing programs about such scams on (IIRC) 20/20 and similar programs, usually involving overseas adoptions in which the scammers acquire children from poor families under the guise someone would provide for their children until the bio parents are able to care for them. IMO it's likely the "pastor," Briggs, is at the center of a bogus adoption ring and Arianna had been adopted out.
When Nicole's body was found, was the $600 still with her?
On the night of April 1, 2016, Nicole takes out $600 from an ATM and tells Goyette she's running an errand.
<snip>
https://crimewatchdaily.com/2017/03...-hold-key-to-mothers-murder-in-san-francisco/
I wonder if the babysitters were bribing Nicole, or if Nicole believed offering them money would entice them to release Adrianna to her. Did Nicole's killer take the $600? Maybe Nicole knew that the babysitters and their associates were interested in money. They may have already received money for Adrianna in a bogus adoption.
If Adrianna is still alive and is the victim of an unlawful adoption, there is a very good chance she will learn this at some point, and evidence will lead to the perpetrators.
4. Was Adrianna's dad active in her life? I haven't read anything about him. I wonder if the babysitters/pastor know him and would have handed Adrianna over to him, possibly for a sum of money. Briggs, at least, seemed highly interested in money.
Friends and coworkers say Fitts complained that Briggs was too controlling and that she had to get away from her. Briggs admits that she could be tough on Fitts, but she says that's only because she loved her like a daughter. "I'm a nosy mom, I'm overbearing yeah, I'm controlling yes, I'm supposed to be
this is my home."
Fitts also told friends that the Briggs charged her rent and made her buy groceries for the household. Between that and money for childcare, there was little left over.
<snip>
http://www.ktvu.com/news/121832978-story
All is JMO