Firefighters battled the blaze for more than two hours, and investigators hope they will determine what caused the blaze, RTV6's Chance Walser reported.

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All that was left was a woven web of charred wood for investigators to sift through at 16 Park.

"The investigators are on scene, along with ATF, Indianapolis Housing Authority are all beginning their investigation, gathering their information and kind of getting a starting point," said Indianapolis fire Capt. Rita Burris.

Smoke could be seen rising from the blaze in Hamilton County and Johnson County, attesting to the ferocity of the fire.

Fire officials said it's fortunate that no one was seriously injured.

"IHA wants to thank the men and women of the Indianapolis Fire Department and the Indianapolis Metropolitan Police Department. Their work to control the scene and stop the fire from spreading was nothing short of remarkable," IHA said in a news release.

Insurance agents were working to determine the cost of the damage to a building that would have housed dozens of affordable units. Indianapolis fire investigators preliminarily put that figure at $3.5 million.

The agency said its first priority is providing IFD with all the information needed to conduct the investigation and that it wants to know more about the cause before considering whether to rebuild.