Two people arrested, after a nine-year-old boy found in a critical condition at a house died, have been bailed.
The boy, named locally as Alfie Scott, died in hospital after a callout to an address on Vashon Drive in Copcut, Droitwich, Worcestershire, on Thursday.
The 39-year-old man was arrested on suspicion of murder and the woman, 33, was held on suspected child neglect.
Police said the cause of death was not yet known and they were "continuing to treat this as an unexplained death".
The boy had yet to be formally identified, the West Mercia force has said, though his next of kin had been informed.
It stated it was supporting the victim's family and "would ask they are given privacy during this tragic event".
Emergency services, including two air ambulances, were called to the address shortly after 14:30 GMT on Thursday.
The man and the woman were released on bail on Friday night whilst the investigation continues.
They had been bailed until 19 March, police said.