Det Chief Insp Allan Harder revealed how the teenage girl was walking back from her friend’s house intending to go home on Easter Sunday, April 5.
However, as she walking down a snicket near the cemetery in Knaresborough she was grabbed by a male and pulled into the school grounds of King James’s School.
The teenager was then subject to a serious sexual assault and DCI Harder said he is keen to identify and trace people in the vaccinity of the school between 9am and 11am.
North Yorkshire Police yesterday released a description of a suspect in the investigation as 5ft 7ins to 6ft in height, of large build, muscular and heavy boned.
Police say he was wearing baggy black trousers and an oversized black hoodie with a large pocket to the front and his face was covered.
North Yorkshire Police have also identified, through CCTV, two male witnesses walking through the school at 7am and 9am, and say they would like to speak to them.
DCI Harder thanked members of public who have already come forward and stressed any information could be ‘crucial’ to the investigation.
He said: “There has been a lot of activity in relation to the initial response and search for the offender and examination of the scene. There were also high visibility patrols in and around the Knaresborough and surrounding area.
“But I would explain that these types of attacks are rare and that is why we need to ensure we are exploring every opportunity to identify who is responsible for this.
“There are a number of lines of enquiry that are being pursued by detectives to do that by the serious crime team and also the major crime team.”
Anyone with information is asked to call police on 101, selecting option two and asking for Harrogate CID.
Crimestoppers can be contacted anonymously on 0800 555111, quoting reference 12150055295.