A nanny whom Russian police have described as being “clearly insane” for parading the severed head of a child around Moscow’s streets Monday reportedly told authorities that she was driven mad after discovering her husband had been cheating on her.

Gyulcherkhra Bobokulova, a native of Uzbekistan, was arrested Monday morning outside a Moscow subway station after carrying the head of a 4-year-old child, while yelling "I'm a terrorist!" and "Allahu Akbar,” The Telegraph reports.

Authorities believe the nanny, 38, strangled and then beheaded the girl -- who had been in her care for 18 months -- with a kitchen knife before setting fire to the family’s Moscow apartment and running out the door with the head in a plastic bag.

Russian police said the woman was “clearly insane” and have yet to establish a motive for the crime, according to The Telegraph. But Bobokulova reportedly told authorities that she had gone mad after learning that her husband – whose current whereabouts are unknown – is with another woman.

“About a month ago she returned to Uzbekistan to get a new passport,” a police source told the Russian newspaper Life News. “When she got home she learnt that her husband had taken a new family. He offered to make her his second wife.”

The child’s parents – who were not identified – said in an interview with police that Bobokulova got along great with their daughter and did not consider her a threat, despite noticing that she had become emotionally unstable in recent weeks, The Telegraph reports.

She was taken back to the apartment around midnight Monday to lead police through the scene of the crime.

As she walked the streets, hecklers gathered and shouted at Bobokulova that her head needs to be “needs to be torn off” as retribution for the killing, The Sun reported.

Hundreds of flowers and toys have since been laid around the subway station where Bobokulova was taken into custody, in memory of the girl.

While Russian newspapers and websites covered the murder, the country’s state-owned television channels appeared to ignore the story, The Telegraph reports.

The story was kept off-air because of government concerns that the murder could stoke ethnic tensions, two employees of the stations told the Russian newspaper RBK.

But the Kremlin denied that it had imposed a blackout.

“It’s not like that. The broadcasters themselves chose not to show insanity. But we support their decision,” said Dmitry Peskov, Vladimir Putin’s press secretary.

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