A burglar beat two elderly people to death in their homes to steal a watch and jewellery, a court has heard.
Michael Weir, 52, fatally assaulted retired cabbie Leonard Harris, 78, and mother-of-three Rose Seferian, 83, in 1998, the Old Bailey was told.
The original investigation missed clues to the killer but DNA testing had since linked Mr Weir to the attacks after 20 years, the court heard.
Mr Weir, from Hackney, north-east London, denies two charges of murder.
Prosecutor Tom Little QC told how the "defenceless pensioners" were struck repeatedly and knocked to the ground, then "left for death".
On 28 January 1998, Mr Weir allegedly broke into Mr Harris's flat in East Finchley, north London.
Mr Harris was found with serious head injuries calling for help from a communal landing. His wife, Gertrude, also suffered head injuries but survived.
An 18-carat gold Zenith watch that Mr Harris had taken from a German soldier during World War Two and his gold signet ring were missing.
The defendant's DNA was found in a blood scraping from the hallway and a blood-stained glove found outside the Harris flat.
Weeks after the first assault, Ms Seferian was violently assaulted while she was home in alone in her three-bedroom flat in Kensington, west London.
Ms Seferian managed to raise the alarm and her son found her covered in blood and "almost unrecognisable" from her injuries. Three valuable rings had been taken from her.
A palm print was recovered from inside Ms Seferian's flat on a window frame where Mr Weir allegedly broke in but was not matched to the defendant until 2017.
Weir told police he had worked as a handyman at various properties but Mr Little said this was not a "credible" explanation for the scientific evidence.
Mr Little said Weir's potential claim that the police "planted" evidence in 1998 to fit up Mr Weir nearly 20 years later was "bizarre" and defied "all common sense".
The trial continues.