Assault in Texas

My question involves criminal law for the state of: TEXAS

My mother was physically assaulted by a female who walked into her shoe repair shop as a customer. She dropped off her shoes to be fixed then came back next day to pick up and pay. Instead, she pepper sprayed her face, beat her, stomped her face, and stole money.
Mom ran afterward and wrote down the license plate number, and found her receipt that had a cell phone number on it. She was taken to the hospital with head trauma.

Cop that showed up 30 minutes later wouldn't do anything, he even said to me that even if he pulled her over driving that car, he wouldn't be able to do anything because he couldn't identify the owner of the car. We do not know her name, but I thought cops take care of that.
How would this get resolved? It kills me to see her with scars, cuts, and bruises.

Have mom talk to a supervisor at the police department, and indicate that she would be able to identify the woman in an in-person or photo line-up or show-up. If she's the owner of the cell phone (following a subpoena to the phone provider) or car (based on a review of DMV records), they should be able to pull her driver's license photo.

Mom can also consider a civil suit, although that would be primarily to identify the offender; I expect that the person is a deadbeat and wouldn't be able to pay any judgment.