Investigators say the driver of the pickup, described as a man in his 40s, fired into the vehicle, striking Jazmine and wounding her mother, 30-year-old LaPorsha Washington.
Washington said one of her daughters alerted her that Jazmine had been hit by gunfire.
"She said, 'Momma, Jazmine's not moving".
Gonzalez described the shooting as "totally unprovoked".
Investigators say they have an image from surveillance video of a pickup whose driver fired several shots into a vehicle carrying a family, killing a 7-year-old girl and wounding the child's mother.
Golfer Randhawa held on poaching charges
A resident of Gurgaon near Delhi, Randhawa has recently started shooting and took part in several shooting events. He got married to actress Chitrangada Singh for 13 years before the couple got divorced in 2014.
The woman driver, possibly in a panic, was able to flee the scene in her vehicle, racing onto the nearby Belt Parkway before coming to rest on the median.
The 7-year-old was the daughter of the woman who was wounded. "We're going to leave every motive out there as a possibility", Gonzalez said in a separate statement. Authorities are asking the public for tips and appealing to nearby residents and businesses to review surveillance video for the red pickup truck. "So senseless. It's never easy, and extra hard during the holiday season".
Another young girl was injured by shattered glass.
The 30-year-old Washington was expected to recover from her wound.
The Sheldon Independent School District said Jazmine was a second-grader at Monahan Elementary and "will truly be missed by all students and staff".
Anyone with information about the suspect is urged to call Houston CrimeStoppers anonymously at 713-222-8477 for a potential cash reward. "We're extremely upset by this, and I know that our community shares those sentiments as well".