Rhys Davies's family called him a "fun-loving boy who loved a joke"
Detectives investigating a teenager's murder have set up a temporary police station in Cardiff city centre.
Anyone with information about the killing of Rhys Davies, 17, of Tredegar, is being urged to visit the mobile station in St Mary Street.
It is near a Ladbrokes shop where Rhys was assaulted on Friday evening after he and a friend became involved in an argument with passers-by.
South Wales Police want to trace three men and a woman.
Rhys, received head injuries in the assault near the junction of St Mary Street and Wharton Street at about 1840 GMT on Friday.
The teenager, who was on a building course at Coleg Gwent in Ebbw Vale, had been shopping with a friend and they were on their way back to the bus station.
Rhys died the next day at the University Hospital of Wales.
The police station will be staffed from 1400-2200 GMT each day until Monday.
Rhys was assaulted near Ladbrokes early on Friday evening
The police station which will be staffed by unformed officers and detectives from 2pm until 10pm each day until Monday.
More than 400 posters appealing for information will also be given to city centre premises.
'State of shock'
His family said they had been left "in a state of shock" by the death, and his many friends were devastated.
Police have issued the following descriptions of the people they want to trace:
• The first man is white, aged 23 to 24, of average build, 5ft 8in - 5ft 9in (1.72m - 1.75m), with dark brown hair, and a goatee beard. He was wearing glasses, a red T-shirt, jeans and a light coloured jacket.
• The woman is white, possibly pregnant, about 20, of average build, 5ft to 5ft 5in (1.52m - 1.65m), with dyed blonde hair. She was wearing a dark green hooded top.
• The second man has dark coloured skin, aged 19 - 21, slim, 5ft 8in to 5ft 10in (1.72m - 1.78m). He was wearing a white peaked cap, a white hooded top and jeans.
• The third man has dark coloured skin, aged 18 to 20, slim, 5ft 7in to 5ft 9in (1.7m - 1.75m), wearing a light coloured peaked cap, a light coloured hooded top, and trainers.
Police also want to speak to a man who was riding a bike who was wearing a black donkey-style jacket with an orange tabard.
Anyone with information can go to the mobile police station, or contact the incident room at Fairwater on 029 2057 1530 or call Crimestoppers anonymously on 0800 555 111.