A "bully" was allegedly filmed pouring a bottle of Coke over a 12-year-old girl on a school bus.
Police are probing the incident involving George Stephenson High School pupils.
Sources close to the victim claim pupils surrounded the girl with their phones as abuse was hurled at her before one of them doused her in the fizzy drink.
The incident is said to have left the youngster "petrified".
The Killingworth school initially told ChronicleLive it was dealing with the incident.
However a source that knows the victim branded that "rubbish".
The source said: "The pupil involved in this was given a couple of days isolation and banned from the bus for three months - how's that dealing with it?"
"Now she's going back to school as if nothing has happened - I can't believe it, I just can't believe it.
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"I am gobsmacked that this is all the school's done - they say they want to give them a second chance but there is no concern for the girl who has been bullied.
"They are treating this like it is some sort of schoolyard scuffle but I feel like we are being laughed at."
The school's head teacher, Ian Wilkinson, said it didn't comment on individual cases.
However he added: "We take every allegation of bullying extremely seriously, whether it occurs on or off the school premises.
"We have an open-door policy so that students or parents can come to us at any time to raise concerns.
"We guarantee they will always receive our full support and that incidents such as this are dealt with in an appropriate manner.”
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The 1,200-pupil school, most recently told by Ofsted that it requires improvement, is understood to have requested footage of the incident from the bus operator.
The family source claims footage was shot on-board by pupils on their phones, but fear it was filmed via Snapchat - and may have now vanished.
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A Northumbria Police spokesperson said: “On March 27, police received a report that a girl had been assaulted on a school bus travelling on Killingworth Way, North Tyneside.
“It was reported that the victim was approached by a girl, who poured a bottle of Coke over her head.
“Enquiries are ongoing into the incident, and officers have spoken to the victim’s family and the school in question.
“Although a full investigation needs to be carried out, this incident does cause us concern and this type of behaviour is unacceptable.
"Those involved need to be aware that this kind of bullying is a criminal offence and the police will get involved.
“Anyone who is the victim of this type of offending should not suffer in silence, please tell an adult or a teacher and you will receive support."
