Video report by ITV News Correspondent Dan Rivers
Three teenagers have been jailed over the killing of a 13-year-old boy in Reading.
Olly Stephens was attacked in Bugs Bottom park in January.
The teenager was convinced to go to the park by a 14-year-old girl, where he was then "ambushed" by two boys and stabbed to death.
One 14-year-old boy has been jailed for a minimum of 13 years, while another 14-year-old boy has been jailed for 12 years. Both have already served 260 days of those sentences.
The 14-year-old girl, who pleaded guilty to manslaughter, has been jailed for 38 months.
The teenagers can't be named for legal reasons.
Watch: Olly's father Stuart says the family's own 'life sentence has just begun'
A jury had previously found the two boys guilty of murder after deliberating for just over 18 hours.
The older boy was further found guilty of perverting the course of justice by disposing of the clothes he wore when the incident took place.
The court heard how both boys had "grievances" with Olly, who had autism, while the girl is said to have described any violence against him as "karma" in the run-up to his death.
Ahead of the trial, the 14-year-old girl admitted responsibility for her part in the teenager’s death.
The attackers left Olly with stab wounds to the chest and back after a short scuffle at the scene.
The Crown Prosecution Service reviewed material containing thousands of messages from conversations the teenagers had on their phones and social media accounts.
The messages had referenced knives, with one video showing the younger boy brandishing a knife at the older boy a week before the attack.
Deleted messages were also retrieved in which the defendants admitted their involvement in Olly’s death.
Watch: DCI Andy Howard, Thames Valley Police
Sentencing at Reading Crown Court on Friday, Judge Heather Norton said: "What you did was utterly cruel and utterly pointless, you have taken one life and you have damaged your own futures and you have caused so much pain to so many people.
"No one can say how your lives and how Olly's life may have turned out if you had not acted with such cruelty and such stupidity.
"The effects of what you did will stay with you, your families and with Olly's family for ever."