The suspect wanted in connection with a botched burglary at the home of Richard Osborn-Brooks has been arrested.
Billy Jeeves, 28, is said to have fled the scene in Hither Green, south-east London, after Henry Vincent was fatally stabbed by the pensioner.
Mr Osborn-Brooks, 78, was arrested on suspicion of murdering 37-year-old Vincent while defending his South Park Crescent home on April 4, before being released without charge.
Scotland Yard said Jeeves was arrested in north Kent at around 5.30pm on Friday on suspicion of two counts of burglary, theft and possession of a controlled substance.
He has been taken to a Kent police station.
Police said inquiries continue but that no other suspects are being sought in connection with the investigation.
Since the incident, Vincent's friends and family have sparked outrage among locals in the usually quiet south London neighbourhood by laying flowers and cards opposite the still boarded-up home of Mr Osborn-Brooks and his wife Maureen.
The tributes have repeatedly been torn down by neighbours and well-wishers angry that the career criminal is being remembered in such a way, only to spring up again within days.
Mr and Mrs Osborn-Brooks are reportedly living in a safe house and plan to sell their property.