A woman has been charged with the murder of a five-year-old boy.
Lincoln Button died at an address in Windstar Drive in South Ockendon, Essex, on 15 December.
A woman was taken to hospital for treatment and she was arrested and questioned after her condition improved.
Claire Button, 35, of Windstar Drive, South Ockendon, has been charged with murder and is due to appear before magistrates in Southend on Monday.
Det Ch Insp Alan Blakesley, from Essex Police, said: "This continues to prove to be an immensely complex investigation into the death of a young child.
"My thoughts and the thoughts of all the investigative team remain with the family of Lincoln Button as we continue to support them through this awful time.
"It has taken a huge amount of work and dedication from the investigative team to reach this stage in our investigation and I would continue to call upon the public to refrain from speculating about the circumstances around this case."
In a statement released last week, Bonnygate Primary School said it was working closely with the authorities as Lincoln's death was investigated.
"His love for school, laughter and cuddles will be remembered and missed dearly," said a spokesperson.
"The school's priority is to support those within the community who need help to come to terms with this tragic loss."
Members of his family also said in a statement: "Link was a cherished, loved, sweet, beautiful young soul who was adored by all and will be sorely missed every day."