Police were questioning four people tonight after a six-year-old boy died when he plunged from the eighth floor of a tower block.
A woman, two men and a teenage girl were arrested on suspicion of neglecting Liam Shackleton, who fell from the window of a flat in Leeds.
Social workers were not involved with the family but the city's Safeguarding Children Board said it is planning to oversee a review into the circumstances of the death yesterday.
Neighbours said the youngster moved into the flat in Lindsey Mount recently along with his parents, Martin and Tanya Shackleton, and two brothers and sister.
It is understood Mr Shackleton's father was the tenant of the property.
Speaking to ITV News, a devastated Martin Shackleton said his son had ADHD and described him as "hyperactive".
He said: "I'm in bits. I heard the news yesterday teatime and I've been in a right state ever since."
West Yorkshire Police would not confirm who is being questioned. A force spokesman would only say those in custody were two men aged 57 and 36, a 28-year-old woman and a 16-year-old girl.
Jane Warden, 51, a care worker, said she saw Liam on the ground after he fell.
She said: "He was lying, face up, with his little arms and legs all twisted.
"There was no blood but his breathing was very shallow and his lips were blue.
"I knew then he was gone, no little kiddie could survive something like that.
"Around 10 people had gathered around and someone put a blanket over Liam until the paramedic arrived.
"He scooped Liam up into his arms and put him in the ambulance."
Miss Warden said she often saw the family at a shopping precinct in the centre of the estate.
"The kids were always very well-behaved and usually had a sweetie or a lollipop in their hand," she said.
"Their parents must be heartbroken.
"Last night I went home and hugged my granddaughter - she's the same age as Liam - and I wouldn't let her go."
Other neighbours described Mr Shackleton as a "grafter", saying he worked hard to feed his family.
A makeshift memorial of teddy bears and flowers were left by well-wishers close to the spot where the child hit the ground.
On pink notepaper attached to a teddy bear, a message from Mama and Julie read: "Such a shame, such a young age and to be taken like that.
"Dear Father in Heaven, dear Father above, please guide and protect the ones that we love and guide them from danger. Guide them from fear for this child is so dear."
Another card said: "Sweet dreams little one love Jennifer, Paula and Mike."
A third card was written to a "very brave and well-behaved little boy".
Police were called at about 5.15pm yesterday.
Liam was taken to Leeds General Infirmary but died a short time later.
Jane Held, chair of the Leeds Safeguarding Children Board, said: "We are saddened to hear about the tragic and untimely death of Liam Adam Shackleton.
"Our thoughts are with his family and friends at this difficult time.
"The police are still investigating the incident and we are working with them as appropriate.
"As is usual in such circumstances, the Leeds Safeguarding Children Board will now oversee a review into the circumstances of the death.
"We can confirm that Leeds Social Care was not involved or working with the family at the time of Liam's death.
"We can also confirm that the flat was in the name of a single male tenant and that the windows in the block of flats did incorporate safety measures which meet current building regulations requirements.
"As investigations are ongoing, it is not appropriate for us to comment further."