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An investigation team with the federal Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) will join the probe of the Sunday fire that destroyed an apartment complex under construction in Salt Lake City.

The ATF National Response Team (NRT) will work jointly with the Salt Lake City Fire Department to determine the origin of the four-alarm fire at 540 E. 500 South,which caused at least $2.5 million in damage, according to a Tuesday news release from the ATF.

"ATF is committed to investigating this fire alongside our state and local partners. We will share our fire investigation expertise and resources to thoroughly examine the origin and cause of the fire," said Special Agent in Charge Luke Franey of the ATF's Denver Field Division.

The ATF team, which tends to be made up of 15 to 18 people, is expected to arrive Tuesday afternoon and will plan with Salt Lake City's investigators on how best to inspect the rubble, starting Wednesday morning. The extra eyes and veteran experience will benefit both the city's investigators and the speed of the probe, especially given the size of the building, said Salt Lake City fire spokesman Jasen Asay. The complex encompasses 64,000 square feet.

"Salt Lake City Fire is looking forward to working alongside the Nation Response Team throughout the duration of this investigation," said Salt Lake City Fire Investigations Capt. Bryon Meyer. "The experience and resources this team brings are invaluable to the outcome of this investigation."

The apartment complex burned for more than an hour Sunday evening before dozens of firefighters doused it. No one was hurt.

A hands-on investigation of the site has been delayed while crews removed a heat-damaged construction crane and razed the top two floors of the building to prevent the risk of falling debris.

U.S. Development, which was building the complex, told the fire officials that the construction site did not yet have any utilities or heat sources. Construction crews had not been there since Friday, and firefighters had made a routine walk-through inspection of the building on Saturday, said Asay.

The investigators expect to have an answer sometime this week.

U.S. Development tore down existing buildings and began constructing the apartment complex last June. Crews expected to finish the 61-unit complex, called Newhouse, by June.

Much of the lumber comprising the building was charred, but the underground parking garage and foundation might prove salvageable. The garage is flooded from the firefighting effort, so investigators must wait until the water has been pumped out — a process underway Tuesday — before inspecting the damage there.

Once the wreckage is cleared and everything salvageable has been saved, the company plans to rebuild, depending on a go-ahead from its insurance company and the city.

The 500 East block of 500 South was still closed off Tuesday while the investigation continues, according to the Utah Department of Transportation.

ATF is the federal agency with jurisdiction for investigating fires and crimes of arson.

But Asay clarified that ATF's involvement is merely due to the size of the fire. At this point, investigators have no indication that arson is a factor.

In addition to investigating hundreds of large fire scenes, the NRT has also been sent to scenes such as the 1993 World Trade Center bombing, the 1995 Oklahoma City Murrah Federal Building bombing and the 9/11 Pentagon crash site, as well as explosions at explosives and ammunition manufacturing plants, legal fireworks factories and illegal explosive device manufacturing operations, according to the ATF news release.

The NRT typically has veteran special agents who have post blast and fire origin-and-cause expertise; forensic chemists; explosives enforcement officers; fire-protection engineers; accelerant-detection canines; explosives-detection canines; intelligence support; computer forensic support; and forensic audit support. Further complementing the team's efforts are technical, legal and intelligence advisers. A fleet of fully equipped response vehicles strategically located throughout the United States provides logistical support.

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