Christopher Ainscough was 50 years old when he was found dead at his home in Windmill Court, Shoot-Up Hill, Kilburn, in December 1983.
He had suffered head injuries at some point between the 2 and 5 December.
The Metropolitan Police launched a murder investigation but were unable to identify his attacker.
Tragically they were also never able to locate his family.
The case remained unsolved over the following years but in late 2020 someone claiming to know about the murder attended a police station.
On 2 February 2021 Anthony Kemp, 58 (13.05.62), of no fixed address, was arrested and charged with murder.
Police are still appealing for information from anyone who knew Christopher, who was born in Dublin, or his family.
Detective Chief Inspector Simon Harding of the Specialist Crime Command said: “It is nearly 40 years since Christopher Ainscough was murdered and given the significant development in this investigation, we are now putting renewed vigour into identifying his next of kin so we can inform them of this latest news.
“If you knew Christopher or his family circumstances then please get in touch – we want to let his family to know that Christopher remains at the centre of our thoughts and we are doing all we can to get justice for him and his loved ones.”
Anyone that can assist is asked to call the police incident room on 020 8721 4205.