A 15-year-old girl has reported that she was raped at the Bestival music event.
The teenager has told detectives that she was with friends in the main arena of the festival at Robin Hill Country Park on the Isle of Wight on Sunday when she was approached by a man she did not know.
She said she was raped some time between 7.30pm and 8.30pm near the main arena.
The attacker was described as black, in his 20s, approximately 6ft tall, and of large muscular build with braided hair.
He was wearing a white top with a navy blue collar and navy blue short sleeves, and wellington boots.
A Hampshire police spokesman said: "Police are appealing for witnesses who know this man or who may have seen someone matching this description walking with a teenage girl in or near the Bestival main area on the evening of Sunday.
"Officers are also appealing to this man directly to make contact so the full circumstances can be established as soon as possible.
"The 15-year-old girl, who is from the Isle of Wight, is being looked after by police officers and staff with expertise in dealing with sexual offences.
"Her family are being kept informed about the investigation. Bestival promoters are assisting police with inquiries."
The weekend event, run by Radio 1 DJ Rob Da Bank, attracted 50,000 revellers and featured headline performances by The Cure, Bjork and Pendulum.