Five teenagers have been arrested on suspicion of conspiracy to commit murder, after a 13-year-old boy was stabbed to death.
Officers were called just before 4pm on Sunday afternoon following reports of an attack in Bugs Bottom fields, Emmer Green in Reading.
Thames Valley Police were called to the "serious incident" and confirmed a schoolboy had died.
A murder investigation was launched after the young teen was stabbed.
The five teens, boys and girls, all aged 13 or 14, remain in police custody.
Earlier this evening, Thames Valley Police said in a statement on Sunday evening: "Tragically, a 13-year-old boy died of his injuries at the scene.
"The victim’s next of kin are aware and are being supported by specially trained officers, but at present, no formal identification has taken place."
They had earlier warned the public not to approach the area.
One local resident who was in Gravel Hill Road said: "I know it was a young teen who has been stabbed. I have heard that he has died and that murder squad police are at the scene.
"I feel so desperately sad for the lad's parents – what must they be going through – so soon after Christmas and into the New Year? It is a real tragedy. I haven't heard what sparked the attack but the fact the scene is in a field is quite unusual."
Det Supt Kevin Brown from Thames Valley Police said: "This is a tragic and shocking incident which has resulted in the death of a young boy.
"We have specially trained family liaison officers supporting the boy's family and the thoughts of all of us within the force are with them at this extremely distressing time."
He added in an update: "This remains a very active investigation and a large scene-watch remains in place.
"We have arrested five young people in connection with this tragic incident, but I would urge anybody who has any information surrounding what happened yesterday to please make contact with Thames Valley Police."
Police are appealing for anyone who was in the area between 3pm and 4.30pm 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.
Anyone with information is asked to call police on 101 or Crimestoppers anonymously on 0800 555111.