Hours after the screaming stopped, neighbors said they watched as firefighters and police officers gathered on the narrow cul-de-sac of Nolan Court in North Homewood and hung their heads in silent prayer, facing the blackened facade of home where a young mother and her three children perished.

Around midnight, when the fire was spotted, neighbors, police officers, and firefighters tried to reach 23-year-old Indera Coulverson and three of her children but were pushed back by thick flames that spread quickly throughout the upper floors of the rowhouse. Coulverson's body - along with those of her sons Ky'Yrik, 6, and My'Zhirik McCullough, 7, and her daughter, Ni'Miyah Crawford, 3 - was found on the third floor.

"Sometimes, despite our best efforts, we don't have the desired result," Chief Darryl Jones said at the scene early Thursday morning. "It hits the family hard. It hits the neighborhood. It hits the fire bureau."

Throughout the day, arson investigators, police, and public officials streamed in and out of the building as authorities worked to determine the cause of the fire and if anything could have been done to prevent the tragedy. As of late Thursday, police had not determined the cause of the fire.

Coulverson called 911 at 12:03 a.m. and told dispatchers that she had awakened to find her mattress on fire on the second floor of 1264 Nolan Court, off Mohler Street and Brushton Avenue. Moments later, firefighters learned that there were four people trapped inside. Witnesses told police that Coulverson's boyfriend was alerted to the blaze by one of the boys, who had come down the stairs for a bucket for water, which he used in failed efforts to put out the blaze. The man and Coulverson's 3-year-old daughter Ir'Riya got out. Coulverson tried to pull the children to safety but became entrapped by the powerful flames.

Kenya Mollett, 17, and her 13-year-old cousin Shaniya Gomez said they saw the fire from their home a half-block away. In bare feet, the two rushed to the scene with Mollett's sister. Mollett and her sister pushed through the front door and found the boyfriend "rushing around" and little Ir'Riya on the couch, crying. Mollett grabbed the girl and ran outside, handing her to Gomez, who carried her back to their home and gave her a Popsicle to calm her down.

Dominique Akrie, who lives in an adjacent home, said she heard the patter of footsteps of people running as she sat in bed. Then she heard yelling outside.

She looked out the front window and saw flames in the corner of her eye. People were yelling and banging on her door, telling her to get out.

With her children and husband Terrence, she fled out the back door and saw her neighbor's boyfriend standing in the backyard, staring at the helplessly at the house with a look of shell shock, his cheeks wet with tears.

Her husband tried to get in through the back door, but flames had spread from wall to wall on the back end of the first floor.

Later, as neighbors streamed out of their houses, they said police officers pushed several people back as they tried to get into the burning structure, hearing someone scream "Help me!" from inside.

Firefighters had the blaze under control by 12:45 a.m., Chief Jones said.

Later Thursday, he added that firefighters were debriefed and counseled by a chaplain who came to the scene.

The official cause of the fire remains under investigation, said police Cmdr. Thomas Stangrecki, who was among those at the scene. City arson investigators, who routinely probe deadly fires, were still conducting interviews and reviewing the 911 call before they would make a final ruling. Neighbors said they heard that the children had been playing with lighters earlier in the day and might have caught the mattress on fire. Both Jones and Stangrecki would say only that investigators are still exploring several theories.

The home, owned by the Pittsburgh Housing Authority, was last inspected June 21, according to officials. Spokeswoman Michelle Jackson said the home's smoke detectors and fire alarms were found to be in working order. Inspectors also look to ensure that egresses are clear of furniture and clothes, so that residents can swiftly exit in an emergency.

"It's a very thorough inspection," she said.

Coulverson abided by tenant rules and had no violations, she added.

The boys were both first graders at Pittsburgh Faison K-5. The district said in a statement that it is "saddened by the very heartbreaking loss."

"Ky'Yrik and My'Zhirik will be greatly missed by all who knew them," the Pittsburgh Public Schools statement said, adding that grief counselors were sent to help students and staff and they would remain there "as long as needed."

Her children often stayed with her mother, Kim Johnson, who lives a few blocks away on Stranahan Street in a brick home. On Thursday, Johnson came to Nolan Court, driven by a housing authority official, where she was met by Councilman Ricky Burgess and Fulton Meacham, head of the housing authority. Burgess hugged the petite woman, offered his condolences and told her, "We will do everything we can to assist you."

Johnson was one of several people who stopped by the home and got out their cars, staring wordlessly at the charred facade. The front door was ajar. A Christmas tree wrapped in shiny tinsel could be seen.

Mayor Luke Ravenstahl toured the home along with Mike Huss, chief of public safety. He said he was shaken by the scene.

"The tragedy of losing four people, especially three young kids, is tough for everybody," he said. "It's just very disturbing thinking about what happened here last night."

That evening, even as rain fell, neighbors, classmates, and young teammates from the boys' youth football league gathered around the home, writing messages on the plywood that boarded the windows and leaving teddy bears, toys, and lit candles. The boys, known as rambunctious, played for the Lincoln Big Cats.

Coulverson was attending Community College of Allegheny County and working at a church, said Akrie. She also did women's hair out of her home.

Burgess, who said he was asked by Coulverson's family to be its spokesman, said they were grateful for the thoughts and prayers of their neighbors but too distraught and overwhelmed to answer reporters' questions. Ir'Riya is in the care of Johnson, he said.

The family needs help paying for "immediate expenses" and funeral arrangements, Burgess said. He helped Johnson set up the Indera Coulverson and Family Memorial Fund through a Homewood branch of PNC Bank, though donations can be made at any branch.

He said he spent much of the day with the family but had not been in touch with Coulverson's boyfriend.

Burgess wouldn't comment on the fire itself, saying, "Let the investigators decide the cause. I'll focus on healing and moving forward.

"I've been a preacher 30 years, and this is one of the saddest things I have ever seen," he added. "Our thoughts and prayers are with the family."

The Medical Examiner's Office said later Thursday that all four family members died of smoke inhalation and carbon monoxide poisoning. Investigators gave the boys' cause of death as accidental, but noted that the manner of death for Coulverson and her daughter was listed as pending while the investigation continues.