The family of Chris Kaba has called for the immediate suspension of the Metropolitan police officer involved in his fatal shooting. The 24-year-old, who was due to become a father for the first time, was shot dead by a firearms officer in Streatham, south London, on Monday night. The Independent Office for Police Conduct (IOPC) has since launched a homicide investigation into his death, yet the Met is yet to confirm if any of those involved have been disciplined. On Saturday, thousands of protesters marched through Whitehall demanding justice for Kaba. Members of Kaba’s family were joined by supporters carrying placards proclaiming “justice for Chris Kaba”, “abolish the Met” and “no justice, no peace”. Protesters gathered in Parliament Square from midday before marching along Whitehall and then on to Scotland Yard. Kaba was driving an Audi, which was reportedly rammed and boxed in by police on Monday night. He was said to have been killed by a single shot fired through the driver’s side of the windscreen of the car. His family has called for the officer who fired the shot to face suspension. In a statement released before the demonstration, Kaba’s family asked the police watchdog to conclude its investigation within “weeks or months, not years”. It added that restoring public confidence in the justice system required the IOPC to make decisions on “a timescale that delivers justice to all concerned”. A statement read: “On being notified of the death of Chris Kaba, the IOPC should have immediately opened a homicide and disciplinary investigation. The family was shocked to learn on Wednesday 7 September that the IOPC had still not done so, and demanded a change of heart without delay. “The family now await the outcome of that investigation, but seek a charging decision in this case in weeks or a few months, not years. Public confidence in the police and our justice system requires the IOPC and CPS to find a way to make decisions in this case on a timescale that delivers justice to all concerned. Avoidable delay is unacceptable. “In the meantime, the family demands that the commissioner of police of the metropolis immediately suspend the firearms officer, pending the outcome of the investigation.” Outside Scotland Yard on Saturday, Kaba’s sobbing mother and relatives sat at the front of the crowd facing the Metropolitan police headquarters. Speeches were made through speakers on the back of a flatbed truck – in defiance of new laws giving police the power to ban loud protests. Drummers played a slow Jamaican nyabinghi rhythm through the rally. After the opening of the IOPC homicide investigation, the family has also demanded the Met release video from body-worn cameras from the officers showing the moment that they shot him. The rapper Stormzy was among those to address the crowd, calling on people to “have stamina” in the campaign for justice. “What they have done is they’ve killed someone. They killed someone, do you know what I mean? … so I just encourage everyone here today to have stamina,” he said. Stafford Scott, the rights campaigner from Tottenham, north London, said: “This ain’t no fight to prove unlawful killing or lawful killing, as the system tries to tell us. Today this is us proclaiming what we know to be true: they killed that young man.” Scott compared the case of Kaba to that of Mark Duggan, shot dead by the Met in Tottenham in 2011. “No matter what they did they had no chance of surviving,” he said. “Within seconds they were executed by racist police who have a strategy of oppressing black people.” Speaking at the protest, Bell Ribeiro-Addy, the MP for Lambeth, the constituency where the shooting occurred, demanded more answers for the grieving family, including the body-cam footage of the officers. Diane Abbott, the MP for Hackney North, told demonstrators: “I don’t know how I would feel if it was my own son killed in cold blood. “[Chris] is not the only black man gunned down by the Metropolitan police.” Lester Holloway, the editor of UK black newspaper the Voice, said: “I’ve had a lifetime of going on these marches. The struggle for justice seems never-ending. But we need to, as a community, keep the pressure on, because otherwise there will be no change.” Temi Mwale, founder of Tottenham rights group the 4Front project, led chants on the March. “If you are black or white we are here because the police killed another unarmed black man in this country.” Destinie Sanchez, 18, from south London, said: “State racism has existed for years and years. Britain is racist to its core … We can bring up all the stop and search stats, all the exclusions of boys specifically in schools and it shows Britain is racist. “Three months ago, Child Q was strip-searched. That was disgusting. How many times have we got to come on these streets to fight back?” Another protester, a musician known as B Yaks from Islington, north London, said: “I’m here to stand in solidarity with a fellow young black male who’s been killed with impunity yet again. It is a reminder of sharp, short institutional racism, especially in the police force.” “They [the police] need to protect us more,” said 24-year-old Nikki from south London. “This isn’t the first time it’s happened. There needs to be a change because they can’t deal with people like that.” Catherine, also from south London, attended the march with her 20-month-old child. She said: “This is a person who has been killed by somebody who is meant to be protecting us. I felt I needed to be here to show some solidarity. It’s not really been in the news at all.”