The blaze at Fero's Bar & Grill in east Denver was reported around 2 a.m. Wednesday, Police Chief Robert White said.
The four women and one man appeared to have suffered other injuries and did not die in the fire, he said.
The five were likely the only ones in the bar when the fire started, so police are asking anyone else who was at the place earlier to come forward, as investigators try to piece together what happened, said police Commander Ronald Saunier.
"The business has obviously been set on fire, an arson, I'm guessing, to mask the homicide that occurred inside," he said.
"There is just trauma, enough information to believe that we have a homicide that occurred here. They didn't perish in the fire."
According to Fero's website, it serves Japanese and bar food.
http://accesswdun.com/article/2012/10/254161