A community is in «absolute shock» after a five-year-old boy died during a family holiday on a Greek island.
Theo Treharne-Jones, from Merthyr Tydfil, was found on Saturday. He is thought to have been found in a swimming pool at a resort on Kos, family in the UK said.
Neighbour Keith Payne said they felt «total disbelief» at the news.
Merthyr Tydfil council said it was supporting staff and pupils at Theo’s school.
Greek authorities confirmed they were investigating the death.
Mr Payne said: «Theo used to play in the street and I’d see him drive around in a toy battery car on this street with his mother, Nina.
«Nina is a lovely lady, we’re just in absolute shock. I heard the news last night and it was just total disbelief.
«It’s so, so sad. They were just meant to be going on a nice family holiday and this has happened. It’s just disbelief.
«Everyone on the street is so upset by it. He was such a nice quiet young lad.»
It is understood Theo had been on holiday with siblings and extended family as part of a group of 10 on the island since Wednesday.
Neighbour Beverley Herbert said they were «a nice family» and Theo was «very pleasant.»
«To go away on holiday and lose a young one like that is horrendous, it’s absolutely horrendous,» she added.
«I just can’t imagine any mother going through something like that.»
A Merthyr Tydfil council spokesman said: «It is with great sadness that the local authority has heard of the death of one of its young pupils – Theo Treharne-Jones – whilst on holiday with his family on Kos.
«Our thoughts and prayers are with his family at this tragic time.
«The local authority will be supporting the staff at Theo’s school and his fellow pupils, as well as supporting the schools which his siblings attend in the county borough.»
Greek police said they arrested the boy’s parents and the hotel manager – adding this is normal procedure following any death.
The parents were arrested on suspicion of exposing minors to danger and the hotel manager was arrested on suspicion of manslaughter by negligence.
All three have been released until the next court hearing, with the date to be confirmed.
Police added a post-mortem examination had been completed with the results of a toxicology report due.
A spokeswoman for holiday operator TUI said: «We are aware of the tragic incident at the Holiday Village Kos, Greece and our thoughts are with the family.
«Our team in resort is currently supporting the family and we will continue to assist in whatever way we can.
«The safety and wellbeing of our customers and staff is our primary concern and our dedicated resort team is working with the authorities and hoteliers.
«As the matter is currently still under investigation it would be inappropriate to comment further at this time».
A Foreign and Commonwealth Office official said: «We are supporting the family of a British child who died in Kos, Greece, and our staff are in touch with the local authorities.»