EDMOND, Okla. - An Edmond mother and her boyfriend are facing murder and child abuse charges following the death of a 2-year-old girl who was rushed to an Oklahoma City hospital in critical condition earlier this month, police announced Monday.

Joseph Joneil Chlebanowski, 26, is charged with first-degree murder and two counts of child abuse. The child's mother, 22-year-old Zyria Ashlyn Walker, faces second-degree murder and one count of child abuse, according to the Edmond Police Department.

The investigation began around 7:12 p.m. Aug. 15 when Edmond police officers were dispatched to a home in the 600 block of Vista Lane to assist the Edmond Fire Department with an unresponsive 2-year-old girl.

Officers arrived before firefighters and immediately began lifesaving efforts, police said. Edmond Fire Department personnel then took over medical treatment.

The girl was transported by ambulance to OU Children's Hospital in critical condition.

Investigators identified Chlebanowski, Walker's boyfriend, as the adult responsible for the 2-year-old and two other children who were in the home at the time.

Police have not released details about how the girl was injured.

Due to the circumstances surrounding the child's injuries and their severity, officers arrested Chlebanowski on child abuse charges.

The girl remained hospitalized but died from her injuries Tuesday, Aug. 18.

Following her death, authorities upgraded the case against Chlebanowski. He now faces first-degree murder and two child abuse counts.

A week after the girl's death, on Aug. 25, Edmond police arrested Walker in connection with the case. She was charged with second-degree murder and child abuse.

Police have not released the child's name or disclosed what investigators believe each defendant did leading up to her death.

The investigation remains ongoing. Anyone with information can contact Edmond Police detectives through the department's Crime Tip Line at 405-359-4466 or Text-A-Tip at 405-625-8398.