MYSTERIOUS mobile phone texts could hold the key to what happened to missing shopworker Jenny Nicholl.

Police last night urged members of the public to help trace the sender of the messages.

Police suspect that the texts from Miss Nicholl's mobile phone were sent after she had been murdered and were intended to throw officers off the scent.

Detectives believe the language used in the messages was an attempt to mimic the 19-year-old.

The texts included information that would only be known by someone close to Miss Nicholl.

Messages were sent to several of the teenager's friends at about noon on Thursday, July 9 - ten days after she disappeard.

Police are refusing to disclose the exact wording of the texts.

However, it is known the messages indicated that Miss Nicholl was safe and well.

Using the latest technology, investigating officers discovered that the messages were sent from the Carlisle area of Cumbria.

Miss Nicholl's father, Brian, was sent a further text message from his daughter's mobile at about noon, on Saturday, July 14.

That text was sent from the Jedburgh area, in the Scottish Borders.

The message included information about mechanical problems with her car. The car had earlier been found abandoned on the outskirts of Richmond, North Yorkshire. The message also contained details of her friends.

Police said there were still many questions remaining unanswered and they appealed for help from the public and the media.

Miss Nicholl's phone, a Nokia 5210, is still missing.

Detective Inspector Pete Martin said finding who sent the texts was a key line of enquiry.

He said: "I would like to appeal for anyone with any information as to a friend or associate of Jenny's who may have visited Carlisle on Saturday, July 9 - the weekend following her disappearance - and also may have visited Jedburgh, on Thursday, July 14.

"There are still a great many questions that remain unanswered in this investigation and we still need the assistance of the public to find those answers."

Police travelled to Cumbria and the Scottish Borders after the texts were sent.

However, inquiries and appeals in the local media failed to produce fresh leads.

Police launched a murder inquiry on Thursday after announcing they had found nothing to indicate that Miss Nicholl was still alive.

Anyone with information is asked to call the witness line on (01423) 539334