Roger Sylvester, 30, died a week after being detained by eight Scotland Yard officers at his Tottenham home in 1999.
The inquest jury said he was unlawfully killed. He had been restrained too long, in the wrong position, it said. But the jury found Mr Sylvester died from brain damage and cardiac arrest, triggered and exacerbated by breathing problems which occurred during the restraint, and also cannabis-induced delirium.