Police released an e-fit of the attacker last year
A 52-year-old man has been arrested in connection with more than 100 attacks and rapes on the elderly across south-east London.
Officers have long believed one person, dubbed the "night stalker", was responsible for a string of burglaries and sex offences dating back to 1990.
The attacks have taken place in areas including Dulwich, Orpington, Norwood, Downham, Lee, West Wickham and Bickley.
Detectives described the arrest of the man early on Sunday as "significant".
Police launched Operation Minstead to track the attacker down in the late 1990s and the investigation covers 108 offences.
Although the vast majority of the victims have been women they also include 10 elderly men, one of whom suffered a sexual attack.
Police say the attacker has raped four victims, one suffering horrific injuries and almost dying in surgery.
Telephone lines and fuse boxes are often disabled before the homes of vulnerable people are broken into. Some of the victims were raped and sexually assaulted.
Earlier this month, the Met Police revealed more than 2,000 DNA samples had been obtained from suspects as part of the 12-year inquiry at a cost of £102,700.
Operation Minstead involves a 29-strong team based at Lewisham police station investigating sex attacks on men and women aged between 68 and 93.
A Metropolitan Police spokesman said: "We can confirm a 52-year-old man was arrested in the early hours of Sunday morning in a pre-planned operation. He is currently in custody at a London police station."