MINNEAPOLIS (WCCO) — An explosion at a private school in south Minneapolis killed two people Wednesday.

The blast happened at about 10:30 a.m. at the Upper School of Minnehaha Academy, a private Christian school for students in preschool through 12th grade.

Here is the latest information:

9:45 p.m.

The Minneapolis Fire Department confirmed that the body of John Carlson was discovered in the rubble at about 8 p.m. Investigators will return to the school Thursday morning.

7 p.m.

A vigil had to be moved from a nearby church because so many people wanted to uplift the Minnehaha Academy community.

Hundreds of students, parents and community members met instead at the academy’s Lower and Middle School, about a mile from the scene of Wednesday morning’s tragedy.

6 p.m.

Crews knocked down the remaining walls of Minnehaha Academy’s Upper School in order to get heavy equipment in to aid first responders in the search for a custodian.

Officials say John Carlson, is still missing. An article from last spring in the school’s student-run online newspaper says Carlson graduated from the school, as did his children. He has worked at the school for more than 13 years. The article also says Carlson often handed out ice cream bars to students.

‘She Welcomed Everyone With A Smile’

School officials say Ruth Berg was killed in Wednesday morning’s explosion.

Berg worked as a receptionist there for 17 years.

“She welcomed everyone with a smile and was always willing to go the extra mile to help our students, families and staff,” officials said.

Her fiancé says they were planning to get married in October.

The Injured

Nine people were taken to Hennepin County Medical Center. Most suffered broken bones and head injuries from flying bricks and debris.

By late Wednesday afternoon, one of the victims — Bryan Duffey — was still in critical condition. Duffey is an assistant soccer coach and a custodian at the school.

Three other victims are in satisfactory condition, and five were discharged from the hospital.

No children in the school’s summer program were hurt in the incident.

The Cause Of The Explosion

Minneapolis police say contractors doing work on the building ruptured a gas line, causing the explosion.

According to city records, Minneapolis issued a permit for Master Mechanical, Inc., to work on the building.

Master Mechanical, based in Eagan, released this statement:

Our thoughts and prayers are with everyone involved in this tragedy and especially with the families and loved ones of those who have died or who have been injured.

We are forever grateful to those first responders and bystanders who came to the aid of all of the injured, including our employees.

We continue to monitor the situation and are working in full cooperation with the Minneapolis Fire Department. At this time, we are referring all questions about the event to the Minneapolis Fire Department out of respect for their continued efforts.

‘It Knocked Me Off My Feet’

The explosion happened near the school’s office and maintenance area. Neighbors said they heard the “boom” from blocks away.

“Live across the street from Minnehaha Academy, heard the blast, felt the window shake,” said Deborah Dillaway. “The dogs were startled and came out 30 seconds later, saw where the building used to be one continuous building now had a gap. I could see sunlight all the way through to the other side.”

Residents felt a tremendous blast, and some could even smell natural gas in the neighborhood. When they looked over, all they saw was a cloud of dust and piles of rubble.

Witness Paul Meskan

Jack Mahler was playing soccer nearby when the explosion occurred.

“Smoke went up and knocked most of us back,” Mahler said. “It knocked me off my feet.”

Witness Jack Mahler

Within seconds of the powerful explosion, residents poured onto sidewalks and front lawns, stunned at the burning pile of rubble that moments before was a century-old school building.

Dillaway said it felt like an earthquake.

“I was just sitting, reading the paper and there was just a huge blast,” Dillaway said. “We used to live in San Francisco, and there are two types [of earthquakes]: one is a short, quick one, the other is a longer one. It felt like the plates were shifting.”

Moments after rescuers pulled a critically-injured man away from the debris, burning gas made it too dangerous to search for any others.

“We have been able to confirm that the explosion, the collapse was caused by a gas explosion,” said Bryan Tyner, assistant chief of the Minneapolis Fire Department. “It may be where we can move it brick by brick, or where we have to get heavy equipment to move the bigger slabs or portions of the building.”

Read More: Community Responses To Minnehaha Academy Explosion

A number of former students were stopping by to see the damage for themselves.

They told WCCO that the building was built back in 1913, and they had celebrated its centennial just a few years ago.