At a news conference Friday afternoon, Ted McKinney, a member of the Indiana State Fair Commission, said Thornton Tomasetti, a New York-based engineering firm, and Witt Associates, a Washington, D.C.-based crisis management firm, both hired by the fair to investigate the incident, were on scene and gathering preliminary information.

Special Section: Indiana State Fair Stage Collapse | Watch:

"We are committed, the governor is committed to bringing forth the very best in the world to assess what happened in a truthful, transparent manner and then provide that to you (the media) and the public," McKinney said.

Thornton Tomasetti will investigate the structural collapse itself, while Witt Associates will examine the state fair's preparedness and reaction to the incident.

"The common thread that we find (when investigating similar tragedies) is really the human factor, people communicating with each other, so that's what we normally see in major incidents, the normal breakdown is sometimes communication," said Kenneth Mallette, a vice president with Witt Associates.

Both firms will provide the state fair with a full report on the incident, along with recommendations, if applicable. The process could take until the end of the year.

McKinney would not speculate about the cost of the investigations.

"We don't know. We're still finalizing the contracts. We wanted to move that quickly and that decisively, so we don't have that locked down," he said. "And that is certainly beside the point. The most important thing is finding out what went wrong so that we can do whatever needs to be done to make sure it never happens again. … We want the truth, whatever it might be."

State police are conducting the official investigation into the incident, while the Department of Labor is also conducting its own probe because two of the six people killed were working at the time.

The Indiana Attorney General's Office, which is the fair's lawyer, has also assigned a deputy attorney general to the case.

A sixth person died early Friday from injuries suffered when the rigging on the main stage collapsed as 12,000 waited on a concert to begin.

A fund to help the victims and their families has been established by the Central Indiana Community Foundation. Donations can be made online or checks with Indiana State Fair Remembrance Fund in the memo line can be sent to CICF, Attn: Indiana State Fair Remembrance Fund at 615 N. Alabama St. Indianapolis, IN 46204.