A 10-year-old boy died after an apparent accident with a air rifle.
South Wales Police were called to a home in the Lansamlet area of Swansea at 6.15pm yesterday after reports that a child had been injured.
The boy, referred to as Rhys, was taken into intensive care at the city's Morriston hospital, where he later died.
A 12-year-old boy is assisting officers with their investigation into what they are treating as a non-suspicious incident.
"Officers were called to Midland Place at around 6.15pm to reports that a 10-year-old boy had been injured with an air weapon," a police spokesman said today.
"He was conveyed to the intensive care unit of Morriston Hospital where he later died of his injuries.
"The air weapon has been recovered and a 12-year-old boy is assisting police with their investigation."
A lane in Midland Place has been sealed off for forensic examination and house to house inquiries are going on.
The spokesman added: "Families of both boys, who are known to each other, have been informed.
"The police are not treating this incident as suspicious."
Assistant Chief Constable Colette Paul of South Wales Police said: "Our sympathies go out to the family of Rhys, who have lost their lovely boy.
"It is a very difficult time for both families and I ask that their privacy is respected."
Anyone with information is asked to contact the incident room at Cockett police station on 01792 562731.