Drivers or cyclists who captured video footage near the home of a murdered Russian businessman are being asked to contact police.
Former Aeroflot deputy director Nikolai Glushkov was found apparently strangled at his terraced house in Clarence Avenue, New Malden on March 12.
Scotland Yard has appealed for anyone using a dashboard or head mounted camera who captured footage near the 68-year-old's home on March 11 or March 12 to submit the video to police.
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.
Counter-terrorism police are leading the investigation into Mr Glushkov's death, but have stressed that there is no evidence to link it with the attempted murder of former Russian double agent Sergei Skripal and his daughter in Salisbury.
Anyone with information can call police in confidence on 0800 789 321.