A school says its community has been left "reeling" after a 13-year-old boy was stabbed to death in Reading.
Oliver Stephens, known as Olly, was pronounced dead at Bugs Bottom fields, Emmer Green, on Sunday.
Four boys and a girl, all aged 13 or 14, have been arrested on suspicion of conspiracy to commit murder. They remain in custody.
Highdown School and Sixth Form Centre head teacher Rachel Cave described the boy's death as a "total tragedy".
In a statement, she said: "This student was part of our community and many students and staff knew him well.
"Many have been deeply affected by this tragedy.
"In normal circumstances we would open the school and welcome in students for support before the start of the term.
"We are currently unable to do this, of course, but are arranging counselling support and will be establishing an electronic book of condolence."
Ms Cave said the school was "a supportive and close-knit community" which would "work together over the coming days and weeks".
Det Supt Kevin Brown, of Thames Valley Police, said: "Our thoughts remain with Olly's family at this incredibly difficult time."
He added: "This is a tragic and shocking incident which has resulted in the death of a young boy."
The victim's family are being supported by specially trained officers.
Officers were called just before 16:00 GMT on Sunday following reports of an attack.
Officers are appealing for anyone who was in the area between 15:00 and 16:30 who might have taken photos or camera footage to contact them if they notice anything suspicious.
Det Supt Brown said he believed there would have been witnesses to the "dreadful incident" as the area is popular with dog walkers.
A man said his wife was walking their dog through the park on Sunday afternoon when she saw a boy on the ground with several people around him trying to give him first aid.
Another dog walker said she saw a group of young people standing in the woods in Bugs Bottom fields at about 15:30 and described it as "slightly unusual".
Reading East MP Matt Rodda has offered his "deepest condolences" to the boy's family.
I would like to offer my deepest condolences to the family of the boy who was killed in an incident in Emmer Green yesterday. Please contact @ThamesVP if you have any information #rdguk #Caversham #EmmerGreen— Matt Rodda (@MattRodda) January 4, 2021
St Barnabas Church in Emmer Green has invited residents to pray and light a candle in memory of the boy.