JACKSON, Miss. — A former Mississippi police officer will face criminal charges in the death of her 3-year-old daughter, who authorities say was left alone in a parked patrol car for four hours last week, a law enforcement official said.

Hancock County Chief Deputy Don Bass told The Associated Press on Wednesday that officials plan to charge Cassie Barker with manslaughter as soon as she is released from a hospital, possibly as soon as Thursday. It’s unclear if Barker has a lawyer to speak for her. Officials have said she was hospitalized because of the emotional shock of the child’s death.

Hancock County Sheriff’s Investigator Glenn Grannan said Wednesday that investigators have learned that Barker left her daughter alone in a car ate least once before, in nearby Gulfport in April 2015. While officials have spelled the name of the girl as Cheyenn Hyer, her father spells it as Cheyenne Hyer.

The Sun Herald (http://bit.ly/2e3Bpd1) first reported the previous incident, saying Barker left the then 2-year-old girl in the back of her personal vehicle. Police responded and child welfare officials took temporary custody of the girl at the time, the newspaper reported.

Friday, the toddler died after being left in Barker’s patrol car for four hours with the motor running. Grannan said Barker told investigators that she fell asleep while visiting another Long Beach officer, Sgt. Clark Ladner, after both finished working an overnight shift.

“That’s how she lost track of time,” Grannan said.

Barker and Ladner were both fired Tuesday by that city’s Board of Aldermen for violating department policies. Bass said that officials don’t now plan to charge Ladner, who has told officials he didn’t know the girl was in the car. The Sun Herald reported he had taken a sleep aid and also fallen asleep.

Bass and Grannan said it doesn’t matter what Barker was doing while at Ladner’s house, because leaving the child in the first place was the willful act that merits a manslaughter charge.

“If she was there reading encyclopedias, it still happened,” Bass said.

Hancock County Coroner Jim Faulk said Wednesday that the state crime lab in Pearl has yet to complete an autopsy or determine what caused Cheyenne’s death. Officials suspect she died of overexposure to heat. Nearby Gulfport recorded a high temperature of 82 degrees Friday.

“She was found in a car and never responded after she was found,” Faulk said. “They worked and worked and worked on her. It has something to do with being closed in a vehicle.”

Long Beach Police Chief Wayne McDowell has said officers are only supposed to use a patrol car to transport a child while on their way to and from work. Barker and Ladner had been suspended without pay since Friday. They have 10 days to appeal their firings.

Grannan said Barker was disciplined by the Long Beach Police Department following the 2015 incident. Minutes of the Board of Aldermen show Barker was suspended without pay for a week and her one-year probationary period was extended for 90 days as a result of a disciplinary action in 2015 that cited conduct unbecoming a police officer and failure to follow laws.

Ryan Hyer, father of Cheyenne Hyer, has created a GoFundMe account to help with burial expenses.

“She was the happiest, bounciest little girl you have ever seen. She loved animals,” Hyer told the Sun Herald from his home in Jacksonville Beach, Florida. “I’ll miss my little girl.”

Hyer said he and Barker spent two years together before they split. The couple never married.

He said he spent the first two years of 3-year-old Cheyenne’s life helping care for her while her mother attended the police academy.

“I’m just so angry, I’m so angry,” Hyer said.

Follow Jeff Amy at: http://twitter.com/jeffamy . His work can be found at http://bigstory.ap.org/author/jeff-amy .