It started in the sacristy of the chapel at the Virginia Theological Seminary. According to ENS, "The fire began in a trash can left near a heater in the sacristy, Susan Shillinglaw, VTS director of communications, told ENS." From here:
The National Response Team (NRT) from the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), along with agents from the ATF Falls Church Field Division and Alexandria Fire Marshal's Office investigators have completed the on-scene investigation into the cause of the Oct. 22 fire at the chapel located at the Virginia Theological Seminary at 3737 Seminary Rd.
The cause of the fire was ruled to be accidental, announced Alexandria Fire Chief Adam Thiel and Willie Brownlee, Special Agent in Charge, ATF National Response Team Special Agent in Charge. Investigators can say conclusively that the fire did start in the sacristy of the Chapel and was accidental in nature.
Over the course of six days, a team of investigators from ATF and the Alexandria Fire Marshal's Office methodically removed the debris from the heavily damaged structure. The team of investigators took photographs, recovered fire debris from the scene for laboratory analysis, and conducted more than 40 interviews throughout the campus. The ATF National Response Team departed Alexandria Thursday.
The fire at the historic chapel was reported to the Fire Department at 3:49 p.m., Oct. 22. Firefighters reported heavy smoke and fire coming from the Chapel located on the Seminary campus upon their arrival. A second alarm and subsequent special alarm were dispatched to assist in fighting the fire. The chapel sustained significant fire damage including a roof collapse.
"Because of the safe and effective firefighting operations by Alexandria and our surrounding jurisdictions, we were able to save the adjacent historic structures, as well as a number of irreplaceable religious artifacts," said Thiel. "Because our fire and EMS personnel train on safe fire ground practices along with continuous oversight by our Health and Safety Unit we were able to avoid any firefighter injuries during this major incident."
Due to the size of the incident, Alexandria Fire Investigators requested assistance from the NRT. Alexandria Fire Marshals and ATF investigators worked together as a team over the course of the investigation to determine the origin and cause of the fire.
"This investigation highlights what happens when investigators work together with a common goal in mind," said Brownlee. "Our agents and laboratory personnel worked seamlessly with the Alexandria Fire Department and Fire Marshal's Office to determine the cause of the fire that damaged the historic chapel at the Virginia Theological Seminary, which has special meaning and memories for many people."