A Year 9 girl accused of trying to stab a teacher "has had problems in class before", a classmate claimed to MailOnline today.Ysgol Duffryn Aman secondary school was placed on lockdown yesterday after a schoolgirl allegedly “went mad” with a knife in the playground. Three people were treated for non-life-threatening injuries.The teenager who is accused stabbed another student before attacking two teachers with a knife, was led away in handcuffs after being arrested on suspicion of attempted... Read this story