Stephen Lawrence's brother claimed to have been stopped by police up to 25 times because of his skin colour as he launched a legal battle against the Metropolitan Police.
Stuart Lawrence, 35, alleges officers from Scotland Yard have repeatedly targeted him as part of a sustained campaign of harassment.
The teacher, whose teenage brother was murdered in a racist attack, has now consulted lawyers over the "ludicrous" police action. He said he was moved to act after he was pulled over by two officers in November while he sat in his VW Scirocco near his home in Peckham, south London. When he asked why he was stopped, one officer told him the pair were "naturally suspicious" of him, he claimed.
He told a newspaper: "I am being targeted because of the colour of my skin, I don't think it's because I am Stephen's brother. Whenever I have been stopped, I have never subsequently been charged with anything, and nothing has ever been found to be wrong with my car. I have never, ever done anything wrong. I have never been in trouble with the law. I have paid my road tax and my insurance, and always tried to keep my cars in a roadworthy state."
He said he has been stopped around 25 times but was pulled over at police checkpoints - where officers were apparently checking drivers' tax and insurance - on only two of these occasions. This was down to "no other reason, apart from racism", he said.
A letter of complaint was sent to Metropolitan Police commissioner Sir Bernard Hogan-Howe on Tuesday, naming the officers allegedly involved in the latest incident.
Mr Lawrence, who is engaged to be married and has a two-year-old son, said he felt "angry and frustrated" and believed there had been little progress in the way police deal with black people.
His brother was stabbed to death by a gang of five or six attackers in Eltham, south-east London, in 1993, at the age of 18. The original investigation into his death failed to solve the case and was dogged by allegations of corruption and racism.
The Macpherson Inquiry later concluded the Metropolitan Police was "institutionally racist". Only two of the killers have been convicted. Gary Dobson and David Norris were found guilty by a jury at the Old Bailey last year after a cold case review team discovered tiny traces of forensic evidence linking them to the murder.
A Scotland Yard spokesman said: "Mr Lawrence's complaint, which we received last night, is a very serious matter and it will be investigated thoroughly and speedily. Stop and search is an important tool to combat crime and is supported by the community if it is used professionally and fairly.