Police have confirmed that the death of a 10-year-old boy in Coupar Angus is being treated as murder.
Officers discovered the body of Kane Morris after being called to a house in Union Street at about 02:30 on Sunday.
An eight-year-old girl remains in hospital in a critical but stable condition after sustaining injuries during the incident in the Perth and Kinross town.
A 37-year-old man has been arrested in connection with the incident.
Officers say two male witnesses who may have passed the property and heard a disturbance on Sunday morning have come forward.
Det Insp Ross Fitzgerald said: "Our inquiries remain ongoing in order for us to establish the full circumstances of what happened.
"We continue to urge anyone who hasn't spoken to us already to do so."