A 5-year-old girl died and her father and a 15-year-old boy were severely burned in a house fire Wednesday in the Capitol Heights area, Prince George’s County fire officials said.

The children were unconscious and did not have a pulse when firefighters found them, said Mark Brady, a fire department spokesman. They were rescued by firefighters and other emergency workers through a rear window on the second floor, Brady said.

Fire Chief Marc Bashoor happened to be nearby and went to the duplex, in the 6300 block of Carrington Court. He arrived in time to see the rescue.

Later, he heard that paramedics, who performed CPR on the children, had revived them by the time they got to the hospital.

“I can’t even begin to tell you how I feel,” Bashoor said. “While I’m extremely proud, I’m distraught for the family.”

Brady announced the girl’s death shortly before 10 p.m., expressing the department’s “profound sadness.”

She had been taken to Prince George’s Hospital Center but was not in stable enough condition to be transferred to MedStar Washington Hospital Center’s burn unit, as the other victims were. All three also suffered from severe smoke inhalation.

Firefighters and rescue workers “gave their best effort,” Brady said.

The names of the victims had not been released Wednesday night.

A neighbor who lives near the scene of the fire said she was going shopping when she saw flames coming out of the duplex.

“I started screaming for help,” said the neighbor, Janette Gibson. She said she often saw the girl riding her bike in the cul de sac in front of her house.

Firefighters received the 911 call about 4:30 p.m. and found the injured man, 24, in the front yard of the duplex. The man, identified by a relative as the girl’s father and the 15-year-old’s brother, told firefighters that two people were trapped upstairs, Brady said.

Donte Maynard, who said he is a cousin of the man’s, said the girl, boy and man had lived in the duplex for several years, along with the man’s mother. The woman, who was not injured, was taken to the hospital because of emotional distress, Brady said.

Maynard said he grew up in the duplex years ago and described the 15-year-old boy as seriously into sports, especially football. The girl, he said before her death was announced, was “a happy, upbeat, pretty, outgoing little girl.”

“They just love life and are happy-go-lucky kids,” Maynard said. “This is just eating me up.”

Authorities were investigating the cause of the fire at the duplex, which Brady said had two working smoke detectors inside. The fire in the house, which is off Martin Luther King Jr. Highway, about 11 / 2 miles east of the D.C. border, apparently started on the first floor. It was extinguished within 30 minutes.