Dan Hunt
BBC News, Leicester
NEMM
Eight children from the camp at Stathern Lodge were taken to hospital
Police have been given more time to question a man arrested on suspicion of administering poison at a children's summer camp in Leicestershire.
Eight children from Stathern Lodge, Canal Lane, and an adult were taken to hospital on Monday amid what locals described as "crazy" scenes but have since been discharged.
A 76-year-old man was arrested at a nearby pub on Monday evening on suspicion of administering poison or a noxious substance with intent to injure, aggrieve or annoy.
Leicestershire Police said it received a report on Sunday of children feeling unwell, but did not visit the camp until Monday and had referred itself to the Independent Office for Police Conduct (IOPC).
The force said the investigation was being led by the East Midlands Special Operations Unit's major incident team.
The IOPC confirmed it was investigating Leicestershire Police's handling of the incident.
East Midlands Ambulance Service said it received a report of a medical emergency at a private address in the nearby village of Plungar at 16:00 BST on Monday.
A spokesperson said: "We sent a number of resources including four paramedics in ambulance cars, 10 crewed ambulances and responders from the air ambulance were also in attendance."
They added nine patients - eight children and an adult - were taken to Queen's Medical Centre in Nottingham.
NEMM
Investigation work has been continuing at the scene
Neighbours described seeing stressed parents outside Plungar's village hall, which was used as a triage centre for the children on Monday.
A 28-year-old woman who lives near the hall said: "We saw all the ambulances and police cars outside. All the kids were very guarded, they would not let anybody near it.
"Everybody was pretty stressed out. There were like four police cars, critical care teams, an ambulance, there was quite a lot. It was crazy.
"The parents were pretty stressed, they were here until probably 11pm."
A man who also lives on the street said: "I saw maybe one girl with her dad. She had her toy with her. They were waiting around a lot.
"It was a bit surreal I guess, a bit odd because it's quite quiet around here."