An inquest into the death of Russian businessman Nikolay Glushkov is set to open.
Counter-terrorism officers are investigating the murder of the 68-year-old who was found strangled at his home in New Malden, south-west London, on March 12.
The inquest is due to take place at West London Coroner's Court.
His relatives issued a statement through Scotland Yard, in which they said: "We are devastated at the loss of Nikolay and are coming to terms with our grief."
Initially Mr Glushkov's death was treated as unexplained, but four days later - following a post-mortem examination - Scotland Yard launched a murder inquiry.
The businessman, who was close friends with Vladimir Putin critic Boris Berezovsky, was wanted over fraud allegations in his native Russia.
He was also outspoken after Mr Berezovsky died in 2013, refusing to accept that his friend had taken his own life.
Police have stressed that there is no evidence to link this case with the attempted murder of former Russian double agent Sergei Skripal and his daughter in Salisbury.