Four men have been arrested at Heathrow Airport as they tried to leave the country following a fatal drive-by shooting in south London.
Chino Johnson, 27, was gunned down while he was with a group of friends in Ferrey Mews, Brixton, just before 9pm on September 12.
Two women were also injured.
At Heathrow Airport on Tuesday, officers from the Metropolitan Police arrested a 20-year-old man on suspicion of murder and three other men aged 20, 22 and 24 on suspicion of assisting an offender.
Mr Johnson was shot by two suspects who rode a moped past the group and opened fire, before they then fled in the direction of Bennett Road and Dora Way.
Detective Chief Inspector Richard Leonard said: “Despite four arrests having been made, I am still very keen to hear from anyone who has information relating to Chino’s murder.
“If you know something, no matter how insignificant it may seem, please do the right thing and get in touch with us.
“If you do not wish to speak to police, you can also provide information 100% anonymously via the independent charity Crimestoppers.”
Anyone with information can call the incident room on 020 8721 4622, tweet @MetCC, giving the reference 7163/12SEP, or to remain anonymous contact Crimestoppers on 0800 555 111.
Anyone with footage that could assist police can upload it to https://mipp.police.uk/operation/01MPS21S92-PO1.