Ten youths have now been interviewed in connection with assaults in Northumberland where graphic footage was circulated on social media.
It shows young girls kicking, punching and pulling the hair of a number of victims in daylight attacks in Ashington.
Chief Inspector Helena Barron, of Northumbria Police, said that inquiries are ongoing and of the ten youths interviewed, nine have been released under investigation, pending further inquiries, and one has been released with no further action to be taken.
She added: “We will continue to take robust action against anybody found to be participating in this unlawful activity and would encourage people not to share these videos on social media.
“Any new footage should be sent to the police to assist with our investigation.
“Anybody with footage, or any information, should call 101 – quoting reference 1078 03/05/18.”