Though they're not disputing the horror of what the 38-year-old woman did, authorities are saying what she said can't be taken at face value.
"It is obvious that the woman is clearly unstable," Kremlin spokesman Dmitry Peskov said, as reported by state-run Sputnik News
. "It seems to me that one needs to treat the words of such an unstable woman accordingly."
The same story cited Vladimir Markin, a spokesman for investigators, as saying nanny Gulchekhra Bobokulova has schizophrenia.
"The motive of a person with ... schizophrenia at the time of a crime does not usually coincide with the explanation that he gives after the crime," Markin said.
It's not clear if Bobokulova has been diagnosed or examined by a psychiatrist or any other doctor.
Nanny yelled out: 'I am a terrorist'
The first sign of trouble Monday may have been the smoke and fire emanating from the Moscow apartment. The worst, though, was the scene soon thereafter outside Moscow's Oktyabrskoye Pole metro station of a woman holding a severed child's head.
"I am a terrorist," she said, as captured on an amateur video. "I hate you -- the enemy."
That woman, later identified as Bobokulova, also said she was acting in response to Russian President Vladimir Putin's decision to bomb Syria, where terror groups, including ISIS, have thrived.
Her tirade ended when a Moscow policeman
took her down and took her into custody, as seen on video and reported by Sputnik
. The object she'd been holding -- the head of the little girl, reported to be 3 or 4 years old -- then rolled away.
The girl's body was later found in the fire-charred apartment.
Most with schizophrenia are not violent
Bobokulova had arrived in Moscow in January from Uzbekistan, registering then with Russia's Federal Migration Service. She became a nanny for a Moscow family sometime thereafter, though state news -- citing the migration office -- reported
she never obtained a work permit.
On Monday, she reportedly waited for the parents and an older child to leave the Moscow apartment before killing the little girl, setting the fire and heading down to the metro station.
Why, exactly, she did what she did is a mystery.
Schizophrenia is a serious but treatable mental illness often marked by hallucinations, delusions and unusual behaviors. It's not uncommon: One in 100 Americans have it, for example, the American Psychological Association
But most people with schizophrenia are not violent, nor are most violent crimes committed by those with schizophrenia, according to the National Institute of Mental Health
"People with schizophrenia are much more likely to harm themselves than others," that American agency said.