Federal investigators from the ATF are seaching for the reason for Thursday's deadly explosion at the Branch Inn restaurant.

Investigators have brought in heavy equipment Monday to help clear the area, so Pueblo investigators and ATF agents can dig through whats left of the demolished buildings.

Monday was Pueblo City Councilwoman Vera Ortegon's first look at the destruction.

She says the council members were at a conference in Orlando when they got word of the devastation back home.

Ortegon, like everyone else who has visited the site, is shocked.

"I just flew back last night. This is my first chance to see it, and it's absolutely devasting. Worse than what I read, worse than what I was briefed on, and worse than the pictures that you see, " says Ortegon.

Authorities say they are still in "investigatove mode," trying to determine what caused the explosion--a terrible accident, or a deadly crime.