While the on-scene probe has concluded, the investigation into the cause continues.
CHARLESTON -- The blaze that claimed nine firefighters originated in the area of the loading dock. But, just how that fire started remains under investigation.
The ATF announced Saturday morning while the on-scene probe has concluded, the investigation is far from over.
"We're into the white collar part of the investigation," said Earl Woodham, ATF senior special agent, explaining that the phase involves lab work, interviews and analysis.
Federal, state and local investigators have been at the scene for the past few days combing through debris, taking photographs, conducting interviews and collecting evidence.
Agents would not elaborate where on the loading dock in the rear of the store that the blaze started. "I cannot comment further on an on-going investigation," said Ken Chisholm, ATF agent.
The agents said they go into every investigation with an open mind, and the determination to uncover just what happened. Asking for patience, Woodham said just because people won't be able to see them as they have, the work is will not stop.
Mayor Joseph Riley said it's important to learn what happened. "We need to know not only for our benefit, but for our state and communities throughout America."
Riley said he is confident that a thorough probe is being conducted, and in time, there will be questions answered. He added that everyone involved understands how vital it is for firefighters across the country to know what happened.
The mayor went on to express his appreciation for the outpouring of support that Charleston has received since the deadly blaze.
"Yesterday will be unforgettable. The service was beautiful and appropriate. It have us an opportunity to mourn together."
While there has been discussion about erecting a memorial on the site, Riley said the city will take its time before any decision is made on that front. He promised that the fallen heroes will be remembered.
Charleston Police Chief Greg Mullen said his officers will probably maintain security at the fire scene for the next five days or so. They've been there since last Monday night.
After that, the site will be returned back to the owner.
Shortly after 10 a.m. Saturday, the federal investigators pulled out of the parking lot.
The memorial along the sidewalk in front of the building continues to grow. Shirts from fire departments across the country are draped over bushes. Some include hand printed messages.
One reads: "CFD 9 YOU ARE CLEAR TO GO HOME."
As firefighters from Texas and Delaware and residents visited the site Saturday morning, a man was allowed by police to come under the yellow crime scene tape. He started playing Amazing Grace on his bagpipe, and walked slowly as he piped.
Capt. Bruce Bickley, of Fort Wayne Fire Department, said it was just a small tribute to the nine who gave all.
"Eight of us pipers and two drums showed up here yesterday, and played. We were honored to do it."