The Ontario Fire Marshal's Office is investigating after two volunteer firefighters were killed in a blaze at the Dollar Stop in downtown Listowel, Ont.

Kenneth Rea, 56, and Raymond Walter, 30, members of the volunteer fire department were killed when they entered the store to search for any shoppers that may have been trapped inside.

The roof reportedly collapsed on the men after they entered the building.

The fire broke out around 3:30 p.m. on Thursday and witnesses say it appeared to have started on the roof where some work was reportedly being done.

The store was open for business when the fire started, and people reportedly ran in to alert shoppers to the fire.

Chris Williams with the Ontario Fire Marshal's Office told reporters they were working with OPP, structural engineers and local fire services to make the scene safe before the bodies could be removed. Representatives with the Ministry of Labour were also at the scene.

"We have to do some, what's called shoring, there are some interior walls that are still at risk of collapse. We have to shore the scene up," Williams says. "We have to make it safe enough for our investigators to make entry at which point we'll be dealing with documenting the scene inside and working towards the removal of the victims."

The bodies were finally removed from the building Friday afternoon, and dozens of police, firefighters, families and friends gathered near the site. In the area where the bodies passed, about 45 firefighters formed an honour guard.

Police have also reportedly located and spoken with roofers who were working in the area all week.

Remembering the fallen firefighters

Both men were well-known in their communities and the loss has left residents feeling sad and helpless.

Rea, from nearby Atwood, Ont. was the deputy district fire chief for the Atwood fire station. He was married and had three daughters and three grandchildren. He had also recently started a new job at a local car dealership.

He lived next door to the local fire station and is remembered as a great neighbour who loved being a firefighter.

Thirty-year-old Walter was a Listowel resident was married in 2010 and hoping to have children. He worked as an accountant at the firm Ward & Uptigrove. His father was also a firefighter.

Black ribbons have been placed along the streets close to the fire and flags at fire halls in Kitchener, Ont. have been lowered to half mast.

Prime Minister Stephen Harper has issued a statement expressing his condolences to the families, friends and colleagues of the fallen firefighters.

Saying he was deeply saddened he also added "These were remarkable individuals – heroes who volunteered to do life-threatening work to keep their communities safe…Through their caring and civic commitment Raymond and Kenneth made their communities and Canada a better place. They will be honoured and remembered."

Ontario Premier Dalton McGuinty has called the loss tragic, and offered his condolences.

In a statement, he said "Our volunteer firefighters take time away from their families to keep us safe…We rely on their selflessness, and today's tragedy is a solemn reminder that we must never take their sacrifices for granted."

Mayor of North Perth Julie Behrns was close to tears as she spoke to the media, "How saddened we are as a community this evening to have to share this tragic loss. We thank all of our volunteer firefighters and their families for their dedication protecting us."

No details have yet been released on memorial plans for the two firefighters.