(CNN) - The Indiana State Fair was scheduled to reopen Monday with a public memorial service for five people killed when a concert stage collapsed during a storm, officials said.

The fairgrounds were closed Saturday night following the accident, which occurred shortly before the country music duo Sugarland was to take the stage before an audience of about 12,000.

Investigators on Sunday sifted through debris of the stage, trying to determine what caused the accident that also injured 40 people, authorities said.

This morning on American Morning, CNN's Alina Cho talks with Gov. Mitch Daniels on the latest into the investigation.

A massive gust of wind toppled the main stage at a Sugarland concert at the Indiana State Fair on Saturday night, killing five people and injuring dozens of fans who were waiting for the country music band to perform.

Shortly after the collapse, many concertgoers quickly turned into first responders, trying to lift the scaffolding off of the crowd and rushing to treat the injured.

24-year old Jenn Gioe was one of the concertgoers who experienced the disaster firsthand. Gioe was sitting in the seventh row at the concert and witnessed the stage collapse.

Gioe joins Carol Costello on American Morning today to discuss the emergency response effort and to explain what it was like to be in the crowd that night.