The three-car crash and subsequent shooting took place on West Fuqua Street near Sam Houston Parkway.
Officers said two cars were headed south on West Fuqua when they crashed into a black Honda Accord going east along the Beltway feeder road.
Soon after, officers believe someone in one of the cars headed southbound started firing gunshots.
"At some point somebody from one of the two other vehicles on Fuqua got out, shot up the other vehicle, striking a young 8-year-old girl in the backseat. She later died from her injuries at the hospital," said Detective David Stark, with the Houston Police Department.
The girl was identified as DeMaree Atkins.
The child was traveling with her mother, Toyia Thomas, and police believe they were just bystanders.
Officers are looking for the drivers of those two cars. One of the cars, a white Pontiac, remained at the scene but the driver took off. The driver of the other car drove off. Their car is described as a dark sedan, possibly a Toyota, possibly with front-end damage.
Thomas said the third car came up after the initial crash.
"I looked over and thought she was trying to help," Thomas said. "She pulled a gun out of the window and she started shooting. Each one of those bullets hit the back of my car where my baby was. I pulled her out of the car, I didn't even know she had been hit. I thought she was still asleep."
Thomas said she laid her daughter on the ground and when she looked at her jacket, she saw the blood. She said she pulled her daughter's shirt up and saw that the bullet had gone through her.