DETECTIVES have appealed directly to one of the country's worst serial rapists, who could be working as a carer of the elderly.

The rapist has committed 98 crimes - including four rapes and 24 indecent assaults - against the elderly during a 15 year reign of terror in south east London.

Police revealed that the man - dubbed the Nigh Stalker - had also targeted elderly men.

During the fresh appeal at New Scotland Yard, Detective Superintendent Simon Morgan explained the sex attacker, a black man aged between 30 and 40, had targeted four men, and indecently assaulted one of them.

DNA tests have established his ancestors came from the Windward Islands in the Caribbean and his genetic make-up includes American Indian ancestry.

Mr Morgan appealed directly to the suspect, who police describe as a gerontophile - because all his victims have been between the ages of 68 and 93.

"This man has committed terrible offences on extremely vulnerable men and women leaving them shocked, frightened and in some cases seriously hurt. One woman who was raped twice at the age of 88 in 1999 died last month never knowing who did this to her or why," he said.

"The emotional scars were just as bad and for years she has lived in absolute agony. I went to this lady's funeral last month and on behalf of her and all of the other victims I would like to appeal to this man directly and say give yourself up. Your crimes have caused such pain and misery to so many people that it has to stop.

"You know who you are. You know you need help. You know you have to stop."

Police believe he may have cared for an elderly relative and have not ruled out that he once worked or still works with elderly people.

Police believe the man, described as having a round face, broad nose and large lips, has a particular knowledge of the Shirley, Orpington, Warlingham, Coulsden and Forest Hill area where the majority of his crimes have taken place.

He is of athletic build, wears size 10 shoes and is around 5ft 10ins and 6ft 2ins tall.

During conversations with victims the suspect has revealed a particular link with Brighton and that his mum died in 2000.

He also known to have stolen ornaments from victims' homes which police have said may have been kept as trophies.

A £40, 000 reward is being offered for information leading to the sex attacker's identification, arrest and prosecution.

Anyone with information should call the incident room on 020 8721 4640 or Crimestoppers on 0800 555 111.