South Wales Police is investigating a series of robberies in Bute Park on Saturday, August 3 – the day of the Man Utd v AC Milan game and the Homeless World Cup Final.
Two boys aged 15 and 16, and a 15-year-old girl, have been arrested in connection with the robberies and released on bail pending further enquiries.
Between 7.30pm and 11pm, five reports were received of young people approaching strangers and making demands of money and stealing property such as money and mobile phones.
A 16-year-old boy was pushed off his bike and hit with a glass bottle causing a facial injury which required treatment.
Officers would like to speak to anyone who may have witnessed these incidents or may have seen the individuals involved.
They are particularly keen to speak to an unknown man, wearing a red Polo shirt, who was working in the park at the time and spoke to one of the victims about his money being stolen.
One of the suspects is described as wearing a balaclava.
Anyone with information is asked to please contact 101 or Crimestoppers anonymously on 0800 555 111 quoting reference *285311.