Thames Valley Police are investigating a rape which is reported to have taken place on Saturday in Swinley Forest, Bracknell.
The victim, a girl under the age of 16, reported that she was alone in the woods at around 3pm when a man unknown to her, who she had been speaking to, raped her.
She reported it to a member of the public who contacted the police.
A wide area of the woods, around the reported location of the offence, has been cordoned off to allow forensic investigations to take place. The scene watch is likely to remain in place for the rest of the day.
Investigating Officer, Det Ch Insp Rebecca Mears said: “The victim is a young person and we are investigating the report with the sensitivity and care the circumstances require. She is currently being attended by specially trained officers.
“At this stage our officers are still gathering information to establish what exactly has taken place and we would encourage any members of the public who have information they feel may be relevant, to contact the police as soon as possible.”