BERLIN (AP) — A German court said Monday that 10 people indicted over a deadly mass panic at the Love Parade techno music festival in 2010 must stand trial, overturning a lower court's decision last year.

Twenty-one people died on July 24, 2010, in a crush in a packed tunnel that was the sole access point to the music event in Duisburg, in western Germany.

More than 500 people were also injured. The victims included people from Spain, Australia, Italy, Bosnia, China and the Netherlands.

Prosecutors indicted four employees of the event's organizers and six city workers on charges including involuntary manslaughter and bodily harm. They were accused of serious planning failures and failing to monitor security properly.

Last year, the Duisburg state court concluded there wasn't a sufficiently strong case to bring to trial.

However, an appeals court in Duesseldorf said Monday there is a "sufficient probability" of convictions. It said the lower court had set "overly high demands" of the chances of conviction in making its decision.

The Duesseldorf ordered a trial by a different panel of judges in Duisburg. It will be up to the Duisburg court to set dates for the proceedings.