By Dan Whitcomb
LOS ANGELES (Reuters) - A construction fire that gutted an entire city block of downtown Los Angeles and caused up to $30 million in damages was an act of arson, authorities said on Thursday.
Los Angeles Fire Department officials have previously said the blaze, one of the largest structure fires in the city's recent history, was likely arson but no suspects have been arrested or charged.
The conflagration erupted at about 1:30 a.m. on Dec. 8 and quickly destroyed a seven-story luxury apartment complex under construction near the junction of two freeways. Firefighters whose station is located next door to the scene opened their doors to find the entire block-long site engulfed in flames.
The heat was so intense it ignited three floors of an adjacent office high-rise and blew out windows in that building and two others. No one was injured, but road closures in the area brought downtown morning traffic to a virtual gridlock.
"Investigators recovered sufficient evidence to eliminate all known potential accidental causes and determine that the fire was intentionally set," the Los Angeles Fire Department and Bureau of Alcohol, Tobacco, Firearms and Explosives said in a joint statement after searching 75,000 square feet (7,000 square meters) of debris.
The two agencies declined to reveal what they had found at the scene that pointed toward arson, citing the ongoing criminal investigation, but said they had conducted interviews throughout the community and sent potential evidence to the ATF's national laboratory for analysis.
The ATF and fire department said two men seen in videotaped footage of the fire were not considered suspects or persons of interest, but investigators wanted to interview them nonetheless.
In one video clip taken by a freelance news camera crew just after the blaze started, a man in a jacket and ball cap is seen strolling casually down the sidewalk along a chain-link fence bordering the blazing construction site.
He appears to touch the fence as if to see how hot it is, and starts to try climbing over it, before two firefighters pull him off the fence and escort him away.
The man subsequently wandered away without being interviewed by authorities, ATF spokesman Thomas Mangan previously said. He said the firefighters who had grabbed him "had their hands full" at the time.
A second unidentified man wearing a football jersey was caught on surveillance camera footage walking along the same street shortly before the flames erupted.
(Reporting by Dan Whitcomb; Editing by Lisa Shumaker)