Missing schoolgirls Holly Wells and Jessica Chapman were using the internet an hour before they disappeared, detectives have revealed.

An examination of computers taken from the girls' homes has resulted in a "number of lines of inquiry", according to detectives.

These fresh leads come as police admit clues emerging from CCTV pictures of the pair have "run dry".

Police fear the pair might have been lured away by someone they met via the internet.

DS Hankins: Abduction 'likely'

And they have been advised by specialists who profile offenders there is a "reasonable possibility" Holly and Jessica are alive with an abductor, five days after they disappeared near their homes in Soham, Cambridgeshire.

Detective Superintendent David Hankins, heading the inquiry, told BBC Radio 4's Today programme: "Specialists, including offender profilers, have advised us that the circumstances we face here in Cambridgeshire suggest a reasonable possibility they are still with someone who has abducted them

"And there is a strong possibility they are still alive and well."

On Thursday, another senior officer, Det Supt David Beck, urged anyone holding them to contact a solicitor.

He said two computers - one taken from each of the girls' homes - were being checked by experts.

"There are a number of lines of inquiry arising out of that," he added.

Police said the computer at Holly's home, where the girls had spent much of Sunday, was in use for nearly 30 minutes a little over an hour before the youngsters disappeared.

It has also emerged parents in the area were warned about strangers, just weeks before Holly and Jessica disappeared.

The warning came after a man and a woman approached a child at a playgroup next door to the girls' school.

Detectives are also checking call records for Jessica's mobile phone, which she had with her and which has not been found.

The two girls were seen on film

But he insisted they had no direct evidence to indicate Holly and Jessica were being held against their will.

Police have released CCTV pictures of the girls as they walked through a sports centre car park on Sunday at about 1820 BST.

Four potential witnesses seen in the footage were traced by police, but detectives said they had offered no further lines of inquiry.

Det Supt Hankins told BBC Breakfast: "The trail is running dry."

Police have received more than 3,000 calls but most "sightings" are being eliminated.

He said it was "almost impossible to believe" the youngsters had suffered some sort of accident.

Express Newspapers has offered a �1m reward for information, and businessmen and other newspapers have offered rewards totalling more than �200,000.

About 250 officers from five different police forces are searching the Soham area for any clues.

Tests are being carried out on a white van seized from a caravan park in Wentworth, about 10 miles away from Soham, after reports a vehicle was cruising the area on Sunday.

Both girls, who were wearing Manchester United shirts, are white, about 4ft 6in tall and slim.

Jessica is tanned and has shoulder-length brown hair while Holly is fair and has blonde hair.

Anyone with information should call police on 01480 422982.