DETECTIVES searching for missing teenager - Charlene Downes - have been carrying out DNA tests on male volunteers in target areas across the Fylde coast.

Officers began the "unusual" task of conducting the non-compulsory saliva swab forensic tests acting on information from "known associates" of 15-year-old Charlene.

Various town centre businesses around Talbot Road in the resort and a number of private residential areas have been visited so far but more are expected to be approached in the coming weeks.

Detective Inspector Tony Harling said: "It may seem unusual to begin forensic testing in cases such as this where we have turned-up no evidence from the missing person.

"It is not standard practice but we decided to act on information gained from interviews with a number of Charlene's known associates.

"We are not targeting any specific addresses, individuals or organisations but have been given an idea of the areas Charlene was known to have frequented with these associates at night.

"These are the areas where the testing has been carried out. The work is on-going and those who have taken part so far have done so on an entirely voluntary basis."

It is now six months since Charlene, then aged 14, vanished following an evening out with friends at the North Pier, Blackpool, on November 1 last year.

Around 20 officers have been drafted in from across the county to work on establishing the whereabouts of the youngster who lives with her family on Buchanan Street in the resort.

As reported in The Citizen (January 1) police released a picture of black jeans identical to those worn by Charlene when seen last.

In addition to this forces in Yorkshire, West Midlands and Greater Manchester have assisted the investigation following a number of possible sightings in their areas.

The National Missing Persons Helpline have also produced a nationwide poster campaign featuring a recent snapshot of a smiling Charlene underneath the heading 'Missing. Can you help?'

Detective Inspector Harling added: "Charlene has now been missing for a considerable length of time now.

"There's no doubt that this has been a much longer investigation that originally anticipated and we are getting increasingly concerned for her welfare with every day and week that goes past.

"We're just going to continue following up every lead we can until we get some tangible evidence of exactly what has happened to Charlene."

Charlene is described as 5ft 1ins tall, of slim build with straight shoulder-length dark brown hair and blue eyes.

She was last seen wearing a black jumper with white diamonds, black boots and the black jeans which had a gold eagle motif down one side.

Anyone with any information about her disappearance or whereabouts is asked to contact Blackpool Police 01253 293933 or the National Missing Persons Helpline on 0500 700700.