The man, held in Essex, was last night being interviewed by officers at a London police station.
A security camera photograph was released this month showing a man walking with Emanuel Spiteri, the killer's last victim. The picture, taken at Charing Cross railway station, was re-released a week later after being enhanced by computer.
The victims are all believed to have been picked up in gay clubs in London by the serial killer who telephoned police to warn that he would murder one homosexual a week. All five died of strangulation or suffocation. The first victim was Peter Walker, 45, a theatre director found dead in his flat in Battersea, south London, on 8 March.
Nearly three months later the body of Christopher Dunn, 37, a librarian, was discovered at his home in Wealdstone, north London.
On 4 June a marketing director, Perry Bradley III, the 35-year-old son of an American congressman, was found dead at his Kensington home. Five days later the body of Andrew Collier, a 33-year-old care worker, was found in Dalston, east London.
Spiteri, 42, a Maltese chef, was found at his Catford bedsit in south London six days after that.
Three of the victims were HIV positive.Reuse content