INDIANAPOLIS, Indiana (CNN) -- The Indiana State Fair reopened Monday with a public memorial service for five people killed when a concert stage collapsed during a storm.

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.

"While we will never forget this horrific event and those who perished, may we Hoosiers find the courage to unify, rebuild and re-emerge with a stronger heart," said Indiana first lady Cheri Daniels, who attended Saturday's concert and was one of several speakers at Monday's ceremony.

Audience members at the service honored victims with a moment of silence and later sang "Amazing Grace."

Officials Monday were focusing on grieving with victims and beginning repairs to get the fair back underway, Gov. Mitch Daniels told CNN.

"Our first instinct in Indiana is not to go rushing around, looking for scapegoats. It's to take care of business, take care of those who've been hurt and then, of course ... study to see if something could have done better and learn any necessary lessons," he said.

On Sunday he described the stage's collapse as a "freakish accident."

"I'm not saying that we're not going to find many things that could have been done differently," Daniels told CNN Monday. "I'm only saying that I know the people who run this operation. They think safety all the time, and I know that their hearts are broken that, in this case, this event took place as it did."

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

Metal scaffolding fell onto the "Sugarpit," a section usually occupied by Sugarland's most ardent fans, about four minutes after authorities took the stage to warn the crowd to seek shelter, according to a timeline of events released by investigators Sunday.

Forecasters had warned heavy rain and strong winds would hit the fair nearly two hours before the storm moved through Saturday. The National Weather Service estimated winds at 60 to 70 mph.

Video shows the blue canvas top fraying and flapping just seconds before the steel scaffolding gave way, sending a heavy bank of stage lights and metal onto fans closest to the outdoor stage.

The Atlanta-based Sugarland group -- along with its opening act, Sara Bareilles -- canceled their scheduled performance Sunday at the Iowa State Fair. According to the fair's website, "aside from coping with the magnitude of the accident, the ongoing investigation prevents the band from getting what may remain of their stage equipment."

Jennifer Nettles, one half of the Sugarland duo, posted a statement on the group's website Sunday, saying "there are no words to process a moment of this magnitude and gravity."

"There are only prayers for peace in the hearts of the bereft, and prayers of thanksgiving for those who were spared or safe. A piece of our heart is left in that grandstand," Nettles said.

Bareilles, who had just finished her performance when the collapse occurred, tweeted Sunday she was "still thinking of all those affected."

On her website, she wrote: "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. "

She called the emergency response "incredibly quick."

While most of the injured were treated and released from Indiana University Health Methodist Hospital, nine patients were admitted and were still being treated Sunday afternoon, the hospital said. Three children remained at Riley Hospital for Children, the hospital said.

"We're all very much in mourning of the loss of the victims, and we are praying with their families," Cindy Hoye, the fair's executive director said.

The Marion County, Indiana, coroner identified the three women and two men who died as: 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.

Vandam, Goodrich, Bigjohny and Santiago were dead at the scene, while Byrd died later at the hospital, the coroner said.

Friends, colleagues and family gathered Sunday to remember Santiago at Chicago's Howard Brown Health Center, a health care organization for lesbian, gay, bisexual and transgender people, where she worked.

"We have lost a fierce warrior, an amazing activist," said Rosa Yadira Ortiz, board president for Amigas Latinos, a group for lesbian Hispanics in Chicago that Santiago was involved in. "She really brought us all together."

The families of two of those hospitalized released brief statements Sunday, each asking for prayers and privacy.

"Jenny Haskell, a 22-year-old Ball State senior, is very critical at this time," her family said.

A fifth-grader, identified only as Jade, is in critical condition, according to her family.

Allison Hoehn, a concertgoer, said many attendees rushed to those trapped after the stage crumbled.

"We tried to get down to help, but no one was moving," Hoehn said. "The storm came on so fast and the stage just snapped like a toothpick."

Spectators grabbed parts of their seats to assemble makeshift stretchers, she said.

"Everyone rushed to help, and we saw people searching and pulling people out," Hoehn said.

Dust swirled just before a gust of wind rushed in and the stage crashed down, concertgoer Jenna Gioe told CNN Monday.

"It was absolute pandemonium" as crowds rushed to get out of the grandstand, she said. Days after the stage collapse, Gioe said she was still struggling to understand the tragic turn of events.

"It's absolutely baffling ... What actually happened, it's beyond all of us," she said.

CNN's Alan Duke, Chelsea J. Carter, Leslie Tripp and David Williams contributed to this report.