Just weeks after a Baton Rouge police officer was arrested on negligent homicide and accused of causing a crash that injured several people and killed a baby, the child's mother was also arrested on the same charge because police said she failed to properly secure the baby's car seat.

NEW: Car seat placed on center console in crash that killed baby involving off-duty cop, police say.

Brittany Stephens, 20, was arrested Tuesday after police found that her daughter's car seat was not secured and the straps were not adjusted correctly for the child's height, according to her arrest report. Police said the "lack of securing the seat to the vehicle and the loose straps are a contributing factor in the death" of the child and "show gross negligence" on the mother's part.

Stephens was not the driver but told officers she secured the car seat with the baby inside. Police spokesman Sgt. L'Jean McKneely said she was arrested because she "was the person responsible for the buckling of the car seat."

Stephens, of 3161 Winnipeg Drive, Baton Rouge, was booked Tuesday into Parish Prison on one count each of negligent homicide and seat belt violation.

The three other adults in the car with Stephens were also issued traffic citations Tuesday, McKneely said.

Breea Gross, 18, was driving when the crash occurred and was cited for driving without a license, seat belt violation and three counts of child safety restraint violation. Janice Gross, 40, was cited for allowing an unlicensed driver to drive her vehicle and seat belt violation. Seth Eames, 23, also cited for seat belt violation.

McKneely said there were more people riding in the vehicle than seats available.

The crash occurred around 8 p.m. Oct. 12, 2017, when a Baton Rouge Police officer — driving his Corvette 94 mph while off duty — struck the Nissan carrying the four adults and four children. Officer Christopher Manuel was driving north on Airline Highway and crashed into the passenger side of the Nissan, which was turning left onto Florline Boulevard at a green light.

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All of the occupants of the Nissan were taken to the hospital. The one year old, Seyaira Stephens, later died of her injuries.

Manuel, 28, was arrested Feb. 16 on one count each of negligent homicide and speeding. Police said then that Manuel has been on paid administrative leave since the accident. He posted $15,000 bail and was released from jail the same day he was booked.

A blood test showed Manuel was not impaired when the crash occurred, according to Baton Rouge police.

East Baton Rouge District Attorney Hillar Moore III said Tuesday his office has not yet determined whether Stephens or Manuel will face charges, but prosecutors "will review all reports, charges and arrests and make the appropriate decisions based upon facts and law."

Stephens posted $3,600 bond and had been released from jail by Wednesday morning, according to online prison records.