Three teenage girls have been found guilty of the manslaughter of a West Yorkshire schoolgirl.
Aimee Wellock collapsed running for the safety of her home
Aimee Wellock, 15, died near her home in Bradford after she was attacked by the group on 7 June.
Claire Carey, 18, and two girls aged 15 and 17 were bailed at Leeds Crown Court pending sentencing. A 15-year-old boy was cleared of manslaughter.
The jury heard that Aimee had an undiagnosed condition which caused her heart to beat irregularly.
She may have died due to the strain placed on her heart by the attack and by running away, the court was told.
Speaking after the case, her father Alan said: "She was the most beautiful caring, affectionate and happy daughter a family could have wished for."
He said it hurt to think how frightened she would have been when she was attacked.
"Those vicious and unprovoked actions robbed us all of any chance that Aimee would have had of being diagnosed with her heart condition along with any precious future we would ever have had together.
"The memory of that fateful evening in June, finding our daughter dying on the grass, trying to resuscitate her, will stay with us forever."
Aimee collapsed at the Chellow Dene beauty spot and was pronounced dead in hospital.
The three girls were also convicted of affray but the boy was cleared of the charge.
Mr Justice Field said: "All sentencing options are open to the court and there is inevitably a chance that I will decide that they should be sentenced to custody.
"I will make my mind up having considered all the facts of the case and particularly the reports that are going to be produced.
"I will grant bail until sentence on the current conditions."
The judge also said the three girls should obey a curfew between 2230 and 0730.
The court heard Carey had a previous conviction for assault occasioning actual bodily harm in February 2001 and was given a £100 compensation order at Bradford juvenile court.
She also pleaded guilty at the same court in October 2002 to handling stolen goods and was given a curfew order.
Leeds Crown Court was told the 15-year-old girl, who pleaded guilty to affray on the first day of the trial, was currently under treatment by a psychologist.
She also had two previous convictions, one in December 2004 for shoplifting and another in April for taking a pedal cycle without permission.
She admitted both offences and was given a compensation order in each case at Bradford juvenile court.
The 17-year-old girl had no previous convictions.
All three defendants will be sentenced on 19 October.