Police warn Night Stalker has returned

The black-clad intruder, who targets pensioners living alone, has broken into three homes - in Lee, Downham and Norwood - within the last four weeks. The latest attack took place at 2am on Wednesday in Lee. Police said the victim was not injured.

Detectives are also investigating a burglary in Downham and near Bromley on 17 May and one in Norwood on 11 May. On these occasions the suspect is thought to have sexually assaulted two people.

The latest attacks have brought the stalker's total number of raids to at least 104, stretching back 18 years. He has committed 13 sex assaults and four rapes.

The operation to catch the suspect, who is black and wears motorcycle gear, has been one of Scotland Yard's biggest. However, despite the effort to trap him, - codenamed Operation Minstead - the stalker has evaded capture.

Police have used DNA technology to establish he is black with Caribbean origins. Detectives have released an image of him, dressed in black, on a motorbike similar to the one he is believed to use.

Each time he strikes he cuts phone wires and disables light bulbs so his features cannot be seen clearly through his balaclava. Police believe he may live abroad for periods which explains the gaps in the periods of offending.

His attacks have caused widespread concern among elderly people living in the areas of south London where he is known to operate.

A Scotland Yard source said the latest three incidents bore all the hallmarks of the serial attacker. He said: "He is back. We would urge people to be vigilant about their security. The suspect has always struck in clusters and what is happening is very worrying, but it also gives us chances to catch him."

The suspect began his attacks in 1990 but stopped from October 1992 to 1996 and between August 1999 and October 2002. Psychological profilers say the assailant is a gerontophile. His victims' ages range from 68 to 93 - and 10 have been men. A £40,000 reward is on offer for his capture.