Christchurch police are investigating an incident in a man threw a 12-year-old boy into the Avon River and held his head under the water..
Detective Sergeant Richard Quested says three boys were throwing stones into the river in the suburb of Wainoni when a man approached them and assaulted one of the boys on Thursday.
He then threw the boy into the river.
Mr Quested says the boy suffered cuts and bruises and was badly shaken.
Police say the man is Pakeha and was wearing a blue t-shirt and jeans.
He was reported to be a passenger in a small red vehicle, driven by a woman and with two small children in the back.
They have appealed for anyone with information about the incident, by Wainoni Road where it meets Avonside Drive, to contact them.
