Police chief Robert White said there's nothing to indicate the deaths at Fero's Bar & Grill were a murder-suicide, raising the possibility that whoever is responsible is still at large. The victims included one of the bar's owners, a petite 63-year-old described by those who knew her as feisty and hard-working.
"It's very alarming, and that's why it's so important that we investigate it to the fullest," White said.
A police officer on patrol spotted the fire just before 2 a.m., closing time for most Colorado bars. Firefighters found four women and one man dead inside.
The Denver medical examiner said the victims included Young Fero of Aurora. State records identify her as one of the bar's owners, although it wasn't immediately clear if she had a business partner.
The other victims were identified as Daria M. Pohl, 22; Kellene Fallon, 45; Ross Richter, 29; and Tereasa Beesley, 45. Pohl, Fallon and Beesley were from Denver. Richter's hometown wasn't released.
The medical examiner didn't release the cause of death.
The five dead were believed to be the only people in the bar when the fire started, other than the suspect or suspects. Police asked anyone who was there earlier to come forward.
The officer who reported the fire said he heard screams, but investigators said they likely came from bystanders outside.
"Based on the severity of the injuries, we don't think they came from inside," fire department spokesman Lt. Phil Champagne said.
The bar is in a strip mall near the intersection of Alameda Avenue and Colorado Boulevard. It is wedged among a check-cashing store, a tennis shop, a nail salon and a car repair business.
Police said the fire did extensive damage, but little of that was visible from the outside.
The bar attracted both regulars and people staying in nearby hotels, but neighbors said it didn't seem busy most days.
Frequent patron Chris Brady said the bar's customers ranged from "semi-homeless-looking people" to patrons in suits and ties.
He was at the bar for a regular poker game held Tuesdays and won $25 cash before leaving at about 11 p.m.
"There was nobody random or crazy in there," Brady said.
Brady said Fero was known for cooking up beef dishes for customers at a moment's notice and usually would close the bar herself.
She bid him goodnight Tuesday as he paid his tab.
"She said, "Thank you, sweetie. Have a good night,'" Brady said. "I said, `You too.'"
Mike Spinale, one of Fero's neighbors in Aurora, described her as "really nice."
"She didn't speak much, but I know she owned a bar and she worked all the time," Spinale said. "She told me she did everything herself."
A sign posted on Fero's door Wednesday read, "Day sleeper, please don't ring the doorbell! Thank you." It was signed "The sleeper."
Danny Fero, who said he was Young Fero's ex-husband, said he did not know who else might have been at the bar Wednesday morning. He spoke to The Associated Press before authorities confirmed Young Fero was one of the victims.
Danny Fero said he talked with Young Fero about a month ago regarding a visit with their daughter, but she made no mention of any threats. He said he was shocked by the events at the bar he once co-owned with her.
Danny Fero told The Denver Post the two met when he was working as a spokesman and photographer for the U.S. Army in Seoul, South Korea, and she was a clerk at the Korean Ministry of Agriculture. The two later married and had a daughter.
Many years later, Young Fero told her husband the only reason she married him was so she could come to the U.S., Danny Fero told the newspaper.
Jerry Richardson, who maintained an ATM at the bar, described Young Fero as "feisty."
"When she wanted that machine fixed, she would tell you about it," Richardson said.
Few details were immediately known about the other victims.
At an address listed for Pohl, a man who answered the door said, "We're not interested in talking." But neighbors Bert and Suzanne Kasben expressed disbelief that the hardworking, studious 22-year-old was one of the victims.
"She was always working," Bert said, adding he knew she held several waitressing jobs.
The Kasbens said Pohl was one of three sisters in a tight-knit family who often were seen walking their dog in a quiet cul-de-sac in their neighborhood.
Meanwhile, Beesley was listed in state records as the owner of Maxim Lounge, another Denver bar.
Frank Peluso, who works in an office building half a block from Fero's Bar & Grill, said he used to eat lunch at the establishment but hasn't been there in three years. It seemed to be declining and the owners have tried various things to attract more business, including offering karaoke, he said.
"It's one of those places that you wonder how it stays in business," Peluso said.
Resident Matthew Neam said you can't see into the bar because the front windows are frosted. He said he and his friend used to joke about what might be inside.
"I've never gone in there," Neam said. "It always looked kind of sketchy to me."
There is a reward of up to $2,000 to those who can help solve this crime. Call Crime Stoppers at 720-913-7867.
(KUSA-TV © 2012 Multimedia Holdings Corporation with The Associated Press)