A woman and two children were found dead early Wednesday when authorities responded to a 911 call about a shooting at a home in the 4900 block of North Pearl Street.
A third child was undergoing surgery at a nearby hospital and was listed in critical condition. All of the children were believed to be under the age of 11, police said.
Denver Police Lt. Matt Murray said no arrests have been made and there was no reason to believe a killer is on the loose. Murray said police believe a firearm was used in the killings.
"It appears to be an isolated incident," he said.
Murray would not say whether police found a gun on scene. He said police were waiting on a search warrant.
Denver fire spokesman Mark Watson confirmed that paramedics responded to reports of a shooting at 4920 N. Pearl St.
Denver Police Chief Robert White called the incident a "horrible tragedy." No names, relationships or details were released other than that the call came in at 6:55 a.m.
Rosalinda Bustillos, 21, said her father-in-law heard a couple of gunshots around 5 a.m.
"Right after that a truck took off really fast," Bustillos said.
Tires were squealing as the vehicle sped away, she added. Her father-in-law does not speak English and stayed inside because he was scared, Bustillos said. Their two German shepherd dogs started barking loudly.
"It's just scary because we all know each other around here, and we've been here several years," said Bustillos, who works at a towing business on the same block. "This has never happened around here, and I thought it never would."
Frank Jersin, 57, who lives next to the small home where the shootings took place, said he hasn't seen lights on in the house for two years.
"It seems real strange," he said. "It's kind of a mother-in-law house, behind a big house. Both houses have been vacant for two years."
When Jersin went out on his porch Tuesday night he saw lights on in the bigger house
Police investigate after at least two children were killed in a home in the 4900 block of Pearl Street this morning, Feb. 6, 2013. (Kieran Nicholson, The Denver Post)for the first time in two years. When someone saw him looking inside the home, they turned the light out, he added.
He said the smaller home where the three were killed has two small bedrooms, a tiny living room and a little kitchen.
"I'm praying for that mother and those poor children," he said. "What happened there was terrible. The devil won that one."
McArthur Mitchell and Joann Cobb, who live nearby, said the family -- a man, a woman, and three kids -- moved in about three months ago and seemed happy, walking the block with their dog.
"They were friendly, we didn't hear them fighting," Cobb said. She believed the man went to work this morning, before police swarmed the home. "I'm in such a shock. They
A group from Providence Bible Church prays near where three people were found dead on Feb. 6, 2013. (Kieran Nicholson, The Denver Post)were just a happy little family."
Latasha Kelly, who works at a marijuana dispensary nearby, said she often saw three children, two boys and a girl, riding their bikes outside.
"That little girl, she had to be just 7 or 8," Kelly said.
Ann Campbell, who lives across the street from where the shootings happened, said she didn't hear anything until police pounded on her door.
"I'm kind of shook up. I have small kids and I baby-sit kids," Campbell said.
She said the owners of the big house remodeled the home last summer.
Bustillos said there is another towing business located near where the shootings took place. She said there are also apartments in the area; she said she does not know the families in the apartments.
Police have closed 49th Street from Washington to Pearl streets for the investigation.
At the corner of East 49th Avenue and Washington Street, about a block from the home, a dozen or so people gathered Wednesday morning near police tape cordoning off the street. They huddled in prayer.
"We have a heart for this community," said Pepe Rojas, who was among the Providence Bible Church group. "It's very hard to know that this thing happened this morning."
The group didn't know any of the victims, but Providence serves the Globeville community, and the church plans to have a 7 p.m. candlelight vigil, as close to the home as possible, Rojas said.
"It's too much," Rojas said of the incident. "You pray for the community and you pray for the family."
Denver Post reporter Sadie Gurman contributed to this report.