A 16-year-old girl arrested after an attack on a teenager that was filmed on a mobile video phone has been bailed by police until next month.
Becky Smith's brother was shown the video by fellow pupils
Becky Smith, 16, was knocked out and suffered temporary paralysis when she was attacked near her Manchester home.
The teenager from Blackley, who went into a police station voluntarily, was questioned on suspicion of assault, a police spokeswoman said.
The attack was filmed on a mobile phone - a craze known as "happy slapping".
Police said the girl who was arrested had been released on bail until 21 June.
Miss Smith's family have now called for a ban on video phones in schools.
The schoolgirl, who starts taking her GCSEs next week, suffered serious head injuries and spent two days at North Manchester General Hospital after the attack.
Her mother, Georgina Smith, described the attack as "absolutely horrendous".
Mrs Smith said measures needed to be taken to stop the video from being shown.
A spokesman for Plant Hill High School said: "This is a police matter which happened outside school."
Andrew Buckingham, from Victim Support, told the BBC such attacks left victims traumatised for months afterwards.
However, he did not think a mobile phone ban was a good idea, as for some people they were "life savers".
"Clearly you should take away the phones from the perpetrators of happy slap incidents but I think for many young people who use their phones sensibly and responsibly that would be a backward move," he said.
He said the best approach was to educate the perpetrators on the "impact of the crime" and deal with them through the courts.