A two-year-old boy is in a critical condition in hospital after being pulled from a lake in Hampshire.
Police are appealing for witnesses after the boy was found unresponsive in water at Swanwick Lakes, a nature reserve near Fareham, on Sunday.
Hampshire constabulary said an 18-year-old man from Southampton, who officers said was known to the boy, had been arrested in connection with the incident.
Police were called at 8.21pm on Sunday and were at the scene with the ambulance service and fire service, who got the boy out of the water. The child was taken to Southampton general hospital where he remains in a critical but stable condition, police said.
Officers would like to hear from anyone who was in the area between 7.45pm and 8.30pm as they investigate how the boy came to be in the lake.
DI Toby Elcock said: “We know this incident will come as a shock to the local community, but we ask people to please not speculate as we follow up all lines of inquiry to establish how the boy came to be in the water.
“We are keeping an open mind as to what has happened, and we are keen to speak to anyone in the area to help us build up a picture of the circumstances. If you were in the area at this time, please call us. Any information, no matter how small, could prove significant, so please do get in touch.”
People are asked to contact officers on 101 quoting 44210210811 or through the charity Crimestoppers anonymously on 0800 555 111.