In the videos, the girl performed original songs under a fake name, with every video appearing to be shot in the same room of the house where she and her 12 siblings were starved by their own parents.
"I'm accused of everything, accused in all ways, accused of what they say, what they say", she sounds to sing in one of her songs, which many today interpret as a desperate cry of help.
The 17-year-old, who can not be named for legal reasons, also had an Instagram account where she posted selfies and pictures of singer Justin Bieber. But not all of her videos were of her singing, one showed the family's two dogs - with piled clothing in the background as well as dirt on the walls and "grime-smudged doors".
"Good Morning America" reported the girl also appeared to have had an Instagram account.
David Allen and Louise Anna Turpin face life in prison after being charged with torture and animal abuse.
Police and paramedics who were first on the scene reportedly mistook the eldest sibling, aged 29, for a child as she only weighed 37kg. According to CBS News, they are facing 12 counts of torture, seven counts of abuse of a dependent adult, six counts of child abuse or neglect and 12 counts of false imprisonment.
"They're starting from very elementary stuff", she said, but have "progressed very, very well". Nearly all of the siblings were severely malnourished.
Prosecutors last week added three counts of child abuse against both suspects and one new account of assault against Louise Turpin, according to the Desert Sun. Those who saw the children recalled them as thin, pallid and reserved.
David Turpin, 57, and wife Louise, 49, are in custody as they wait for their next court date - 23 March.
Mr Hestrin claimed that the shackling, as well as other punishments - including locking the children in different rooms, depriving them of food and inflicting "frequent beatings and even strangulation" - were used as punishment.
The children were allegedly chained up for months at a time, allowed to shower only twice a year and denied access to a toilet.
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