Murtaza Nazir, 26, died after he was shot in Bagshaw Road, in Stechford, Birmingham, on August 28.
West Midlands Police say they arrested the 22-year-old man on Wednesday night.
He remained in custody for questioning last night.
Two women, aged 22 and 49, were also arrested on suspicion of assisting an offender. They also remained in custody yesterday.
Detective Chief Inspector Scott Griffiths, from the force’s homicide unit, said: "There has been no let-up in our search for Murtaza’s killer and this is a significant step forward in our investigation, but we still need anyone with information to come forward.
"We need to understand what led to this tragedy and find all those involved."
Anyone with information is asked to call police on 101.