A real-life Cracker has been called in by police to help catch a serial sex attacker.

Dr Julian Boon was instrumental last year in catching the murderer of Worthing pensioner Jean Barnes.

The university lecturer specialises in drawing up offender profiles in major criminal cases.

Dr Boon is among a number of crime experts who have travelled to Sussex for a special conference aimed at helping detectives hunting the so-called Thursday Night Rapist.

The conference was organised by officers from the Operation Bobcat squad, who are hunting a man who has raped one woman and attacked 15 others in a reign of terror that began in 1995.

More than 1,000 men living in the Bognor and Chichester area have already given voluntary DNA samples as part of the hunt and a reward of £20,000 has been offered.

But it has so far failed to unmask the man who has attacked victims as young as 12 in subways and other secluded locations in the two towns.

He has been dubbed the Thursday Night Rapist because of the day of the week when most of the attacks have taken place.

The DNA samples have been taken from men living in two areas of Chichester with which detectives believe the man has had links in the past. Other samples have come from men who match the attacker's description or whose movements have come under suspicion.

The conference was attended by officers from forces involved in similar investigations.

The officer in charge of Operation Bobcat, Detective Superintendent Steve Scott, said: "We are as determined today as when the investigation commenced to identify this man.

"By holding meetings when we get all the experts together, we can use not only their experience in their own field but also the knowledge they have from being involved in similar investigations."

Police have revealed they have DNA from two of the attacks, many of which have involved foreign students.

Police have issued a new appeal to students in the Bognor and Chichester areas to take sensible security precautions as the winter nights draw in.

Mr Scott said although no attacks had been linked to the man since May 2000, the investigation was not being scaled down.

Detective Sergeant Georgie Rainey, a senior investigator with the team, has thanked all the men who have already given samples.

She said: "After taking almost 1,000 samples, we know the next person tested may again not be our offender. But on one occasion he will be."