— Firefighters racing to stamp out a mobile home fire Wednesday met with flames shooting from windows as a woman and others looking on pleaded for them to save four young children inside, witnesses told investigators.

All four children, including twin girls, perished. It took firefighters less than 10 minutes to put out the fire once they arrived, and after entering the charred, singlewide home they found the bodies of the twin 1-year-old girls and their brothers ages 3 and 4, authorities said.

The mother was so distraught that it took hours to calm her. Investigators still aren’t sure where she was when the fire started, Darlington County Sheriff Wayne Byrd said.

“Right now we can’t say whether she was inside or not,” Byrd said.

Authorities were keeping everyone but investigators far from the home Wednesday evening near Hartsville, a city of some 8,000 people in the Pee Dee, about 60 miles east of Columbia.

“Our hearts are heavy for these four young children. God have mercy on their souls. We did everything possible to save them,” Hartsville Mayor Mel Pennington said in a statement.

A photograph tweeted by the sheriff showed the outside of the home seemingly relatively undamaged, while the inside looked charred. A tricycle and another children’s toy could be seen in the yard. Smoke could still be seen wafting from an open front door, fire hoses snaking inside.

The burned-out home was just outside the Hartsville city limits, but city firefighters fought the blaze.

Arson investigators planned to work through the night trying to figure out what started the fire. The S.C. State Law Enforcement Division was called in, which that is standard in any fatal fire, the sheriff said.

Autopsies are planned for today to determine the cause of death and confirm the identities of the children, Darlington County Coroner Todd Hardee said. Their names were not released Wednesday.

Bernitha McCrea lived a block away from the family and said she knew the mother well. McCrea wasn’t home when the fire trucks raced down her street. Hours after the fire, deputies weren’t letting her past the crime-scene tape.

“She was a good parent. She would have tried to save them. She loved those babies,” McCrea said.

Roxie McDonald lived next door to the children and their family. She didn’t see the flames over her tall hedges, but knew something was wrong when she heard the sirens.

She didn’t know the mother, but she saw the children frequently playing in the yard. Her house was roped inside crime tape afterward, so she asked deputies if she would be able to get back if she left to go to her church. They told her she could.

“I talked to my pastor,” McDonald said. “We’re not going to have our normal Wednesday night service. We’re just going to pray for the family.”