(Reuters) - Investigators probing an arson fire that gutted a multi-story apartment complex under construction in Los Angeles have found accelerant in the ruins, and are still trying to identify suspects more than a month after the massive blaze, authorities said on Wednesday.
Inspectors have interviewed more than 100 people about the blaze, which caused up to $30 million in damages when it engulfed the scaffolding of a seven-story luxury apartment complex last December in one of the largest structure fires in the city's recent history.
But they are still trying to track down two men seen in video footage approaching the flames, along with other "people of interest," said officials from the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF).
Treading cautiously through the precarious structure, investigators shoveled 1,000 square feet (93 square meters) of debris by hand, said Carlos Canino, special agent in charge of the ATF Los Angeles office.
After the week-long scrub, and aided by surveillance videos and an accelerant detection dog, they discovered accelerant as evidence of arson, he said.
Officials declined to discuss investigation details, but said they expected to offer an award of $170,000 for information on the fire, more than double the sum usually offered for multiple murder cases.
"This is not vandalism, this is an act of violence," said Canino. "It's violence not against a building, but against a whole community."
Officials also asked area residents to disclose any knowledge of "someone with unexplained burns."
The conflagration erupted at about 1:30 a.m. on Dec. 8 and quickly destroyed the construction site. Firefighters whose station is located next door to the scene opened their doors to find the entire block engulfed in flames.
The heat was so intense that it ignited three floors of an adjacent office high-rise and blew out windows in that building and two others. No one was injured.
(Editing by Cynthia Johnston and Sandra Maler)