The 9-year-old Houston girl shot in the head during a road-rage incident was watching cartoons in the back seat of her parents’ SUV at the time — a crime missed by city traffic cams because they weren’t recording, authorities said Monday.

City officials revealed more details of the troubling case as they urged the shooter to turn him- or herself in, while offering a $30,000 reward for information leading to an arrest in last week’s shocking incident.

“Someone knows who the shooter is,” Mayor Sylvester Turner said. “And I encourage that person to pick up the phone and call Crime Stoppers. We are not just going to walk away from this incident.

“When things happen to our babies, when things happen to our kids, we will go that extra step to find you.’’

The wounded child, Ashanti Grant, is in critical condition, fighting for her life, officials said.

Turner said that while Houston’s transportation agency, TransStar, has traffic cameras throughout the city, including on the Southwest Freeway where the shooting took place, the devices weren’t recording at the time. The cameras currently just monitor live traffic conditions.

“Some time ago, a decision was made with all the different partners at TransStar not to video-record,” Turner said, appearing to suggest that the move was made for a legal reason.

“When you’re dealing with road rage, what would have been helpful were to have these cameras to video record the traffic so that you can go back and replay. We could have gone to the recordings and zoomed in,” he said.

He said that decision will be reversed for crime-fighting.

Houston Police Chief Troy Finner tried to pre-empt concerns about recording cars, saying the footage would only be used for criminal cases, not in traffic court.

“Some of those individuals [are] saying there’s too much surveillance, but this is a different time, and nobody is going to use that surveillance equipment to violate anybody’s rights,” he said.

Ashanti was headed to the grocery store with her parents and her 12-year-old brother when police say the driver of a white GMC Denali pickup truck opened fire.

Authorities have said they believe that the family’s car ended up between the Denali and another vehicle that appeared to be racing, and after the Denali cut off the Grants’ Chevy Tahoe several times during the showdown, it then got behind them, and someone in the Denali opened fire on them.

“Our family is crushed right now,” said the girl’s uncle, Larry Grant. “What really crushed me is I found out that my niece was sitting in the back, watching cartoons as this happened.”

“If you know anything, please step forward and say something,” he pleaded.

Ashanti’s parents were in attendance at Monday’s presser but declined to speak.

“They’re standing strong, but you can imagine the pain,” Finner said.

Turner added of the child, “Her situation is improving, but she’s not there yet.

“She’s fighting boldly, and we want to pray for her in a very special way. The entire city is praying for her recovery.

“Ashanti should be in school with her teachers and classmates returning to her family. Instead, she remains in a hospital fighting to recover,” the grim-faced mayor said.

“If that doesn’t move people in this city, I don’t know what will.”

Eyewitness tips have yet to come in, police said Monday. Finner said he was hopeful that would change in the coming days.

“Even the streets have rules,” he said. “And I’m from the streets, I’m from this city.”

“Somebody knows something,” he added, “and we have to stand up.”

Police said they are looking for a Hispanic man between the ages of 20 and 30. The shooter may have had a female passenger in the truck at the time, Finner said.

Congresswoman Sheila Jackson Lee, a Democrat whose district includes much of central Houston, spoke in support of Turner’s anti-crime initiatives.

“[Last year] had 749 children injured by guns,” she said. “We haven’t even gotten into the first quarter, and 82 children across the nation have been injured by gun violence.”

“Don’t think about protecting the perpetrator,” she said in a plea to anyone with information on the road-rage crime. “Think about this family and the pain they are going through.”