News magazine Der Spiegel reported that Sauerland received a copy of a site inspection report dated June 14 – six weeks before the event took place – saying that the site lacked both a safety plan and an adequate fire-safety plan.
The damaging accusation comes from a leaked 32-page interim report on the causes of the disaster, in which dozens of people were crushed near a tunnel leading to the main Love Parade ground.
The site inspection report was addressed to the event organizers, but according to a note, a copy also landed on Sauerland's desk.
The revelation puts further pressure on the mayor, who has consistently refused to consider resignation.
The news also comes one day after one of those responsible for crowd management at the Love Parade admitted making mistakes.
"I should have been more insistent in pointing out the problems," psychologist Carsten Walter said in a recent interview.
Walter, among those responsible for regulating the crowds, said that hours before the deadly crush he had the feeling that something was going wrong, but that he did not have the power to close off the event grounds.