Fourteen children who were arrested under suspicion of murder After the death of the boy on the industrial property in Gateshead were released on the police bail.
The body is believed to be Laytona Carr, who is reported missing, was found in the building.
Northembria Police called in the Fairfield Industrial Park in the Transmission Area Gateshead on Friday evening.
Eleven boys and three girls between the ages of 11 and 14 were arrested under suspicion of murder and remain in police custody.
Earlier, school school remembered as “appreciated and a lot of beloved” students of David Thompson, the main teacher of the Hebburn comprehensive school.
On the Facebook post, he spoke about the “tragic loss of one of our students,” and added, “Our school community is heart.
“Layton was worth a much loved member 9. years, and everyone will miss him very much.
“Sincere condolences We expand to Layt’s family and loved in this incredibly difficult time.
“As a school, we will be mitted together to support each other through this tragedy.”
Anyone who wanted to pay tribute was invited to lay flowers at school.
The police were warned of fire reporting on Friday shortly after 20h.
The fire went out for a short time later, but fears were placed for the missing teenager, who was believed to be at that time.
Police spokesman said: “Unfortunately, the following searches that runs Northumbria police and partners in Tyne and carry fire and rescue service, believes that in the building is located in the building in the building.
“His gender is informed and currently supported by specialist officers.”
In the joint statement, the local councilors Amanda Winther, Ian Patterson and Paul Diston said “share our community about Tragedy” and transferred their good wishes to family and friends.
They said, “We were in contact with residents about concerns about the anti-social behavior in the Berself Industrial Estate and the former place of the former Harrison nearby.”
Among the concerns were among the problems, a broken fence board with the side of the warehouse and the reported fire were among the concerns.
They said that the contact with Securitas, Gateshead Courdes, the fire service and the Severumi Police and “Some Actions” was adopted.
Police Cordon was at the scene on Sunday and blue balloons in the form of number 14, together with the flowering tribents, were among the tribunes that set up the mournful.
One of the messages, attached to a bunch of flowers, read, “Thank you for brightening our lives. You will be missed out of the word.”
The second message said, “Rest in Paradise, Layton. Always in our hearts. Fly high with angels. I took too early. I love you forever.”
The GofundMe page set by a family friend who supports Layton’s mother with buried costs, raised more than £ 11,000 to 7.30.
The Detective of the Louise Jenkins Main Inspector, the Northern Air Police, previously described the events as “an extremely tragic incident in which the boy was unfortunately lost his life.”
She said, “Our thoughts are with Layton’s family because they start trying to process their loved ones.
“Our specialist officers will continue to support them in any way they can.
“We ask that their privacy is respected at this point.”
She said that in force Cordon, while the police were investigating to establish “full circumstances surrounding the incident.”
Officers would be in the area to “offer public conviction,” she added.
Anyone who has information that could help the investigation is invited to contact the north-west police.
The Commissioner with northern crime Susan Dungworth said, “My cordial condolences are with the family and friends of Laytona Carr in this devastating time.
“It keeps me updated by the Chief Officer and its team and want to thank all the emergencies involved in responding and ongoing inquiries.
“I know this will come as a Shock for the Bill Quay community and I echo officer ask for anyone with information to please contact Northumbria police.”