Indiana State Fair
Concertgoers and emergency personnel hold up stage rigging after it collapsed minutes before a concert by Sugarland at the Indiana State Fairgrounds in Indianapolis August 13, 2011. Reuters

Investigators are still investigating exactly what caused stage lighting and rigging to crash down Saturday on a concert stage at the Indiana State Fair, killing five people and injuring dozens.

High winds are believed to have contributed to the incident. The National Weather Service said winds registered at 60-70 mph.

The fair reopened on Monday with a memorial service for the victims. Indiana Governor Mitch Daniels has called the tragedy a "fluke that no one could have foreseen."

About 12,000 fans braved the strong winds to attend the state fair. Sugarland was scheduled to play on stage before it toppled over. The stage and thousands of pounds of metal scaffolding landed directly on "The Sugarpit," which is a place that is reserved for Sugarland's most ardent fans.

Sugarland's lead singer, Jennifer Nettles, said on the group's Web site, "There are no words to process a moment of this magnitude and gravity."

Along with Sugarland, singer Sara Bareilles was supposed to perform at the Indiana State Fair. On her Web site, Bareilles said, "The accident at the Indiana State Fair felt like a bad dream. The weather changed in a matter of minutes and the stage collapsed in a matter of seconds."

According to authorities, most of the injured have been treated and released. A few of the injured are still at either the Indiana University Health Methodist Hospital or the Riley Hospital for Children.

Among the casualties were Tammy Vandam, 42, of Wanatah, Indiana; Glenn Goodrich, 49, of Indianapolis; Alina Bigjohny, 23, of Fort Wayne, Indiana; Christina Santiago, 29, of Chicago; and Nathan Byrd, 51, of Indianapolis. Byrd was pronounced dead at the hospital.

Here is a video of the event. Warning, this is graphic and may not be for everyone's eyes.

Must Read: Sugarland Plans Memorial to Honor Indiana Bluesfest Stage Collapse Victims (PHOTOS)