Child crisis detectives say four children were home alone at the apartment including a 13-year-old girl acting as a babysitter.

When crews arrived, the upstairs apartment was on fire with heavy smoke in the unit. Dispatchers told rescue crews there was an infant still inside.

Firefighters used breathing apparatus to enter the second-story apartment and bring the baby girl out.

TFD and EMSA immediately started CPR on the baby, and she was taken to the hospital. The 11-month-old girl was transferred to Pediatric ICU in critical condition. She was pronounced dead around 6:30 Sunday morning, according to Tulsa police.

Police officers say there were four girls: ages 11 months, 3, 6 and 13 years, at the apartment when the fire broke out. They believe the three younger children were siblings in the care of a 13-year-old relative.

"We're making sure that they're safe in a safe environment right now," said Detective Paula Maker, Tulsa Police.

The mother was located and came to the apartment.

"She works at a bar, and as our understanding - she was at her place of employment," Marker said, "but she had been out with a boyfriend and she was out - she had consumed some alcohol and was dancing.

"It's uncertain at this time if she working or out for pleasure."

The other children made it out of the apartment though the 3-year-old girl was taken to the hospital for observation.

A firefighter had a minor injury in the response as well, but he is expected to be OK.