DETECTIVES investigating the rape of a 15-year-old schoolgirl in Dorchester are still urging residents to help them catch the offender.

The investigation team say that people may have information that, although may seem irrelevant, could prove immensely valuable in the hunt to bring the rapist to justice.

The distressing incident has sent shockwaves through the community, and police are stepping up their efforts to find the man responsible. They are hoping the community can help the investigation.

Dorset Police received a report on Thursday, December 5 – the evening of Dorchester's Christmas Cracker event – that a 15-year-old girl had been raped in the field at St Osmund’s School on Barnes Way. The incident occurred shortly after 9.22pm that evening. The victim was walking along the field when it is reported she was approached from behind by a man – who was carrying a Swiss army-style knife – and forced onto the ground before being sexually assaulted.

The offender has been described as aged in his mid 20s to early 30s and was wearing a light grey Puffa-style jacket with the hood up, light coloured trousers and leather gloves.

A full DNA profile has been recovered, which police believe to be from the offender.

Detective Chief Inspector Richard Dixey, of Dorset Police's Major Crime Investigation Team (MCIT), said the investigation is exploring many different avenues, including speaking to known sex offenders in the area.

"We are investigating several lines of enquiry and that [known local sex offenders] is one of them," he said. "Obviously with the DNA profile most of these previous offenders can be eliminated but this is a line of enquiry. We have numerous lines of enquiries to bring the offender to justice."

He added: "What (the DNA profile) allows us to do is easily eliminate or implicate someone that matches the profile.

"That is why if anyone has any concerns about friends or relatives people that they know were out and about in Dorchester at that time of the Christmas Cracker.

"Previously people might have been afraid to falsely accuse someone but the DNA profile allows us to rule out people as well.

"The speed of any investigation will depends on the information we receive. That is why this appeal to the public is so important.

"Someone might have that important piece of the investigation that they think might be irrelevant and a waste of our time but I would rather have all of the information first."

DNA profiling is a modern version of a fingerprint. Everyone has their own DNA so there can be no mistaking someone's DNA profile for someone else's.

Chief Inspector Jim Beashel of the local Neighbourhood Policing Team said he wanted to reassure the public:

"This is an extremely rare event," he said. "Not just for Dorchester but the whole of Dorset really.

"It's a rare event and we want to make people aware that we are concerned and to urge people to take reasonable steps to protect themselves.

"We will continue to have enhanced patrols in this area who can be approached by members of the public if they have any concerns about anyone they know."

Schools and youth clubs in Dorchester have been visited by the local Neighbourhood Police Team to offer safety advice following the rape.

Chief Insp Beashel said: "Neighbourhood Police Officers have been into all of the middle and secondary schools to provide safety talks as well as local youth clubs.

"I would urge for parents to have conversations with their children to make sure they are staying safe and to not walk home alone, particularly at night.

"If there are any schools or other community groups that want a visit they should go onto the Dorset Police website and book a visit."