Florida State Forester Jim Karels, the investigation lead, said the team committed to produce within 60 days preliminary results into what happened to the crew that was killed when the fire flashed over them, The Arizona Republic reported Wednesday.
"They'll look at the fire behavior on Sunday, what the weather conditions were in the afternoon when this event occurred," said Flagstaff Fire Capt. Bill Morse, a member of the incident information team. "They will ... interview with fireline personnel, witnesses, incident-management team members and gain as much as they can. They'll look at fire department records and reports, pull up radio logs and communications to look at what happened and how things were communicated at that point."
The Republic said the Granite Mountain Hotshots sent a distress call before they died Sunday, but authorities did not disclose information about timing, circumstances or details of any response.
However, fire experts told the newspaper the distress call likely was too late because by then, the crew likely was deploying last-resort foil fire shelters.
As of Wednesday night, the 8,400-acre Yarnell Hill fire was 45 percent contained, Inciweb.org, a national listing of active fires, indicated.
Investigators from the across the country also will determine if or when the crew made other distress calls and what any responses were.
Once investigators examine the location where the firefighters died, they will review documents and radio records to determine a timeline of the Granite Mountain crew's last moments, the Republic said.
"We haven't been privy to radio calls made or not made by the hotshot crew itself," said Matt Benson, a spokesman for Gov. Jan Brewer. "Everybody wants to have a better understanding of what happened and how this tragedy occurred."
The Maricopa County Medical Examiner's Office finished autopsying the victims Wednesday and could release reports on the manner and cause of death for each firefighter Thursday.
The Yavapai County Sheriff's Office said it would search for any additional victims, although no residents have been reported missing.
John Russell, the office's chief deputy, said deputies have a list of structures damaged in the fire, but haven't been able to physically check on residents because of the fire's heat.
"As soon as we can get in there, we will and start checking residences," Russell said.