The Hunt for 'Britain's Most Wanted Man'

He wears a black balaclava and preys on the elderly late at night, breaking into their homes, robbing them and, in some cases, sexually assaulting them. Eighteen years and more than 100 offences later, British police are still struggling to find the "Night Stalker."

Randomly named Operation Minstead, it is Scotland Yard's biggest hunt ever for a serial rapist. Officers have dubbed the stalker "Britain's most wanted man."

Officials believe he has an obsession for the elderly; his victim's ages range from the mid-60s to early 90s, and 10 have been men.

But after nearly two decades of terrorizing the elderly, the Minstead man has shown his face and police have their biggest breakthrough yet. A recent spate of attacks in London led to one women being able to produce an artist's impression of her attacker. Until now, no one had ever seen his face.

Detective Superintendent Simon Morgan is leading the investigation and has been working with the Minstead team for the past eight years.

He told ABC News that the artist's drawing is a big leap forward. "We've got 107 previous victims who haven't seen his face. Since releasing the image we've had a massive amount of phone calls into the inquiry, suggesting possible names, all of which we are currently working through. We've also identified an area where we think he probably lives; it's a small area in southeast London and we're obviously focusing a massive amount of resources down there."

The Minstead stalker is believed to have first struck in 1992, and there is also the possibility that he was active as early as 1990. He was picked up on police radar in 1997 following the forensic link of two rape cases. Despite more than 100 cases now forensically linked, police still haven't been able to catch the night-time predator.

Morgan said it's his toughest case yet. "The man is victimizing the elderly because he knows his chances of being caught are slim. He said at the end of his attacks, 'Thank you. Please give me time to get away before you call the police,' and because they are from a generation where they see the best in everyone, they actually do that."

His break-ins seem to follow a pattern, and he has a number of trademarks that have made it easier to link his crimes. He sits in rear gardens peering through windows to make sure the elderly person is living alone. Then after forcing himself into the house late at night, he goes on to disable the electricity before he wakes his victims by shinning a flashlight in their faces.

The stalker can spend hours in the house and sometimes establishes a connection with his subject. He has been described as soft-spoken, polite and displaying feelings of tenderness toward his victims. Although he doesn't often steal much money, he can put his victims through drawn out, horrific ordeals. The Minstead rapist will also often lie dormant for long periods and then strike a number of times before disappearing again, sometimes for years.

Detective Morgan explained to ABC News that the man is like no other burglar in the country. "He really does have a distinctive approach," he said. "What you need to bear in mind is that breaking into houses at night is quite a rare type of crime, breaking in and staying with the victim, waking them up and interacting with them is very rare and then demanding a sexual element is in its extremes."

During the burglaries there have been four confirmed rapes and 26 indecent assaults. But Morgan believes there could be more. "There are at least two victims who have said that they were burgled but were not sexually assaulted and after they've died their daughters have come forward and said mum was raped," he said.

Criminal profilers working on the investigation have called the man a gerontophile, someone who seeks sexual gratification in the elderly. Morgan said profilers believe this could have stemmed from an experience he had when he was a young man. "He will have had a sexual encounter with an old person and this is either something that he enjoys or is revenge for that elderly attack."

This case has relied heavily on forensic testing, the expertise of criminal profilers and taken up hours of officers time. Detectives even flew to Trinidad in 2006 to make an appeal for information after forensic tests showed the suspect originally came from the Windward Islands.

But even with an $80,000 reward for leading to his identification, the man is still on the loose.