A seven-year-old boy has lost an eye after being struck by a stone while having a picnic with his family in a park.
An inquiry is examining whether the stone was thrown up by a grass-cutting machine in Barry, Vale of Glamorgan.
He was taken to hospital and underwent surgery but the eye could not be saved.
The boy has been named locally as Andrew Attwell, from Barry. South Wales Police and the Health and Safety Executive (HSE) are investigating.
A joint inquiry has been launched into the incident, which happened in Maslin Park at about 1400 BST on Tuesday, 3 August.
Miles Punter of Vale of Glamorgan council said: "We would like to express our deepest sympathies to the young boy and his family.
"This is obviously a very distressing experience for them. The incident is currently under investigation and it would be inappropriate for us to comment at this stage."
An HSE spokesperson said: "I can confirm the Health and Safety Inspectorate is investigating the incident at Maslin Park. We have no further comment to make at this time."
Any witnesses who were in Maslin Park at the time of the incident are asked to contact police on 101 or Crimestoppers anonymously on 0800 555 111.