Through cameras installed in the walls, the investigators watched the blaze from its beginning, starting slowly on a pillow cushion before spreading quickly to the couch and the floor.
The temperature in the room rose until the flashover point, when the blaze was no longer a fire in a room but rather a room on fire — everything in it ignited due to the heat. Flames and smoke filled the room. The picture went dark.
This was the second training fire held on the campus of the Sheppard Pratt psychiatric facility on College Avenue in Ellicott City. This one, held Monday, was designed not for firefighters, however, but for those who arrive after the flames are out.
"It's less about learning how to fight a fire and more about learning how to investigate a fire after the fact," said Special Agent David Cheplak, a spokesman for the federal Bureau of Alcohol, Tobacco, Firearms and Explosives.
A month ago, Howard County firefighters had received real-world experience, practicing putting out fires in a rancher-style home and watching how flames and smoke can behave. A second such exercise was scheduled at an unused two-story house on the campus, but it would have taken too much work to get ready, including stripping away multiple layers of carpet and taking paneling off walls, according to Eric Proctor, a battalion chief with the county Department of Fire and Rescue Services.
But the ATF could still use it, and their training exercise would, in turn, benefit others.
Photos and videos recorded the event, and data was measured by devices inside the home. Information from the exercise will be used in fire investigation classes, held six times a year at the National Fire Academy.
The students will use the data from the exercise to better understand what to look for when working cases, which is often done alongside local fire departments.
"When they go to a scene, they have to look at all the variables and all the facts," said Eric Pena, a senior special agent and certified fire investigator with the ATF's fire research laboratory in Beltsville.
Agents concocted a scenario for this blaze: Four people had been in the home. A man made it out alive, but his wife died in a rear bedroom that had its door open. Their infant child also died in a room with its door cracked open. The man's brother survived, escaping through the back door.
The survivors gave conflicting statements to investigators.
"The investigation is whether they [the victims] were killed intentionally or accidentally," Cheplak said.
The classes will receive photos from the scene, witness statements and an investigator's report on the origin and cause of the fire.
The flames and smoke soon began to billow from the eaves of the home, then burst out a second-story window, a large cloud of gray pouring forth. Firefighters on the scene extinguished the fire, allowing the investigation to begin.
The house is scheduled to be burned to the ground on Tuesday, and the rubble will be removed. But the lessons of what happened in this home won't be forgotten.