HOUSTON -

Investigators are still trying to determine the cause of last Friday’s fire that consumed a southwest Houston hotel and took the lives of four firefighters.

Investigators said they will probably wrap up their work where the Southwest Inn used to stand in the next week and a half.

The final report could take months.

Fire officials said for the first time Tuesday that the four firefighters who died, along with those who were injured, possibly entered the burning building at the northeast side of the structure.

 “It's a tragic event and we're dedicating our investigation to our heroes and our fallen firefighter friends,” said Deputy Chief Ed Arthur of the Houston Fire Department Arson Bureau.

As local, state and federal agents sift through the debris, they are focusing on the area in and above the restaurant’s kitchen. Officials are searching for the ignition point and the reason for why the roof collapsed.

“There are a few layers of roof,” said Arthur. “That is part of the investigation. The low bearing of the structure… that may have been a contributing factor, but we're not ready to come forward and state such.”

Investigators said they have conducted over 100 interviews, including 60 with firefighters who were at the scene. They are trying to create a timeline to document the sequence of events, from the first 911 call, to the distress call and the response.

“We have the best and the brightest out here,” said Arthur. “I'm optimistic. It's possible we have an undetermined ruling but I’m very confident we'll get to the bottom of what caused this tragic event to occur.”