The unnamed officer allegedly kicked Alesia Thomas, 35, in the groin area on July 22. Thomas had dropped her two children, 3 and 12, off at a police station, saying she could not care for them because she was a drug addict.
Police tracked Thomas to her South Los Angeles residence and arrested her on suspicion of child endangerment.
Officers said Thomas fought back and was high on drugs. The report says "[Thomas] was incoherent and kept asking the officers to let her go and told them on several occasions to kill her."
Thomas then kicked as officers tried to place her in a squad car, and then an officer, called Officer D, threatened to kick back. The report said Officer D kicked Thomas "in the groin area three times and forced her back into the vehicle."
Not long after that, Thomas' eyes rolled back in her head inside the squad car and she died at a hospital. The arrest was recorded on camera. It was earlier incorrectly reported she died in the back of a police car.
The commission found three other officers had used appropriate force in the incident. None of the four was named in the report.
An internal investigation into the other officers' actions was expected.
An autopsy found it's "undetermined" if the cocaine in her system or the kicks from the officer caused her death.
Thomas' mother is now suing the city of Los Angeles.
The Associated Press contributed to that report.