DUISBURG, Germany — Prosecutors on Monday opened a criminal investigation into the deaths of 20 young adults who were trampled to death at the Love Parade, as experts accused the techno festival's organizers of ignoring Germany's exemplary safety standards and setting up a death trap.
Prosecutors did not specify who had been named as suspects in the negligent manslaughter probe. But organizers and authorities in the western city of Duisburg have come under fire for allegedly trying to squeeze as many as 1.4 million revelers into too small a space and for allowing the party to go on even after the deaths.
The tragedy Saturday happened near a jammed tunnel that was the only entrance to the festival grounds in an old freight railway station. Police said 511 people were injured.
"This is not a tragic disaster, this is a crime," said Marek Lieberberg, who manages concerts for singers like Shakira and Sting.
He called for the mayor's resignation, saying the disaster was a result of "megalomania" by the city and a huge violation of safety rules that turned the tunnel into a "deadly trap."
German authorities and event organizers have in the past handled massive crowds without a hitch, including at the Catholic youth gathering in 2005 attended by Pope Benedict XVI, the World Cup a year later or past Love Parades that brought out hundreds of thousands of people. But some German authorities and security experts were calling Monday for tighter oversight of festival planning.
Germany's Interior Ministry, which oversees police and security, said the Duisburg tragedy must force a reexamination of security at large events, a day after Chancellor Angela Merkel urged a thorough investigation and called on the country "to do everything" to prevent a similar disaster.
"It is now the duty of all those involved to think about which conclusions have to be drawn," Interior Ministry spokesman, Stefan Paris, said at a news conference in Berlin.
Several officials and event organizers pledged to review planning for upcoming events such as concerts and religious gatherings to make sure they meet security standards.
Much of the criticism of the Duisburg disaster centers on the fact that there was only one way in and out of the festival grounds. The tunnel became a bottleneck and then a scene of horror, as people piled up on each other or scrambled over others who had fallen.
It remains unclear what triggered the panic, but it appears that people trying to escape the surging crowd climbed up a metal stairway in front of the tunnel and then fell and were trampled or crushed.
It's inconceivable that organizers would make hundreds of thousands of people channel into a tunnel that can't be easily evacuated and that doesn't allow rescue teams to get through easily, said Carsten Simon, the managing director of S.A.F.E., which handles security at huge concert venues.
"The most basic thing for such big events really is that you can never have a common entry and exit," Simon told the AP. "You can't allow the crowds to run into each other."
"I cannot understand how the authorities could possibly approve that," he said.
The event should have been stopped immediately, Liebersberg said, because if fear spread among the crowd inside the packed event, the outcome could have been much worse.
Andreas Schadschneider, a physics professor at the University of Cologne who researches evacuation dynamics, said the smallest incident under such circumstances can be fatal.
"The forces in such human crowds are unimaginable," he said.
Similar disasters have brought change in the past. A sweeping modernization of English football stadiums and a transformation of policing methods followed the 1989 disaster at Hillsborough in Sheffield, where 96 people died after being crushed and suffocated in overcrowded sections of the stadium.
A 90-day inquiry by a judge exposed flaws in the way football games were policed in unsafe stadiums, and the British government ruled that all top-flight stadiums would be seating-room only and that perimeter fences would be torn down.
In Germany, the city of Dresden said it would take lessons from Duisburg into account when hosting a big Protestant church event and the woman's football world cup next year, according to a report from the DDP news agency.
The organizers of a huge heavy metal festival planned in the town of Wacken in August said they will now check their security plans again for possible weak points.
Andre Aahrle, whose company Special Security Service says it handles about 1,000 big events per year, said Germany's current requirements are already enough.
"The rules are absolutely sufficient, but only if they are respected," Aahrle said.