A fifth person has been arrested on suspicion of murder following the death of 17-year-old Harry Baker.
The body of the teenager was found at Barry Docks during the early hours of 28 August.
Three men aged 33, 36 and 47, from Barry, and a 38-year-old woman from Carmarthenshire, who were previously arrested on suspicion of murder remain in custody.
Police say Harry’s family have been updated and are being support by specially-trained family liaison officers.
Following his death, Harry's family said he was a "beautiful... fun-loving son" and said their lives will "never be the same again".
Officers are still carrying out "significant police enquiries" and say a number of cordons remain in place in Barry while investigations continue.
Senior Investigating Officer, Detective Chief Inspector Mark O’Shea, Major Crime Investigations Team, said, “Five people are now in custody on suspicion of murder. We would very much like to thank the community for the support and information that has already been provided and would urge anyone else with information to please contact us.
“We are appealing for anyone who may have seen or heard a disturbance in the Cardiff Road and Ffordd Y Mileniwm area in Barry, sometime between midnight and 1am on Wednesday, August 28, to get in contact.”
- Information and digital footage can be submitted online via a public portal https://mipp.police.uk/operation/62SWP19A93-PO1