(NECN: Ally Donnelly) - The scene in Boston's Back Bay was a chaotic one as smoke rose above the skyline and witnesses saw first-hand what was happening.
Confusion was the feeling for many in the neighborhood for most of the day. They saw what they thought was an explosion. Then they saw heavy smoke and fire. Finally, they heard that firefighters were dead.
"It was a deep boom," said Blake Pantalena.
"We just saw smoke coming out, and some people jumping from the windows above," said Sandra Vidacic.
Boston firefighters Lt. Ed Walsh and Michael Kennedy were killed in the blaze.
"They're heroes. I mean, these guys risk their lives every day," said Pantalena.
"It's terrifying. I can't imagine," said Vidacic. "It's a terrible loss."