Keanu Taylor, 25, was shot on Coldharbour Lane in Brixton in the early hours of 2 May.
Fugitive Kevin Parle, from Liverpool, is wanted in connection with two killings on Merseyside.
The initiative includes anonymous reporting and education in schools in a bid to cut crime.
The fraudster posed as a police officer and convinced the victim to hand over cash.
The Atrium Health Club in Tilehurst was severely damaged in the fire early on 30 January.
Deara Sadiq, 21, from Coventry, was identified as the prime suspect in the attack, police say.
Daniel and Liam Poole, from Burgess Hill, have not been heard from since 2019.
It says people who witnessed an attack on Mason Miller, 20, may still have vital information to give.
Police appeal to the public for information in the hunt for murder suspect Zachariah Liburd.
