Late Abraham Badru was the son of House of Representatives member, Hon. Dolapo Badru, representing Lagos Island.
Abraham Badru was shot dead near his home in London.
An 18-year-old female suspect was arrested on Thursday, 22 November and remains in custody.
A £20,000 reward remains on offer for anyone with helpful information.
He died from gun shot wound on his chest.
Detective Chief Inspector Noel McHugh, said: “It has been eight months since Abraham was gunned down on the street in Hackney.
We have been working tirelessly to find out what happened that night and bring those responsible to justice.
More than 600 lines of enquiry, 200 hours of CCTV footage has being reviewed.
“Our investigation is making progress”.