A girl aged 12 was raped by a man at a Milton Keynes play park.
Officers want witnesses to come forward following the report received on Sunday about an attack at 15:00 BST on 23 March.
The girl was on her own in the park in Bradville when a man pulled her into woodland and attacked her.
Police said they are carrying out a forensic examination of the scene, off Harrowden.
The victim is described as white, 5ft, slim, with shoulder length brown hair and glasses.
The man, who was white, about 45 and skinny with short grey and black hair, ran off after the attack.
He spoke with a Scottish accent and was wearing a black leather jacket, blue jeans and black Dr Martens boots, police said.
Det Ch Insp Justin Fletcher said: "We would urge anyone who saw the victim or a man answering this description in the area around that time to contact us as a matter of urgency.
"We take all allegations of a sexual nature very seriously and understand how difficult it can be for victims to come forward."