The claim made by the child in question is that a man walked up behind her at 8:30am while she was walking to school, pulled down the hood of her winter jacket, and started cutting her hijab with a scissors. She screamed and he ran away. She hurried across the road with her brother where they followed a crowd of people "to be safe".
The man then came up behind her again moments later and resumed cutting her hijab. When she noticed him behind her cutting her hijab again, "he just smiled and ran away".
The man managed to cut the hijab twelve inches.
From extensive policing experience, none of this makes sense. The time, the setting, the assault, the risk of getting caught, the return of the smiling man "wearing all black" despite the crowd, no eyewitnesses from the crowd, no alarm raised, and so on, and so on.
For all the above reasons and many more, I don't believe this happened, or it has been greatly, greatly exaggerated.