German prosecutors say they have indicted 10 people on charges including involuntary manslaughter over a mass panic at the Love Parade techno music festival nearly four years ago that resulted in 21 deaths.

Duisburg prosecutor Horst Bien said Wednesday that four employees of the event's organizers and six city workers have been indicted. They face charges of involuntary manslaughter and bodily harm, punishable with up to five years jail time.

He says proceedings against six more people were dropped because there wasn't enough evidence for charges.

The suspects, whose names weren't released, are accused of serious planning failures and failing to follow security procedures properly at the July 24, 2010, event.

The victims were aged 18 to 38 and included foreigners from Spain, Australia, Italy, Bosnia, China and the Netherlands.