Police believe the driver who caused the accident Sunday morning on Highway 67 in Alvarado in Johnson County was drunk.
The woman who died was Maranda Abshire. Her 5 and 2-year-old sons, Crus and Christopher Dominguez, were also killed.
Abshire's 13-year-old sister survived the crash.
The suspect involved, Ricardo Martinez, has been charged with three counts of murder. He was also injured.
Police said Martinez has two previous drunk driving convictions and that his blood alcohol level was more than three times the legal limit when blood was taken from him at the hospital.
For Abshire's sister's injuries, Martinez is charged with intoxication assault.
"All indications we have is that the mother, the victim in the Mustang, did everything right… seatbelting her kids in the proper way, everyone wearing seatbelts," said Chief Brad Anderson with the Alvarado Police Department.
Abshire was studying to be a paralegal. A vigil was held for her Monday night at the Cleburne Chili's, where she'd worked for the past five years as a bartender.
Her friend said she will be missed.
"She was the best single mom. Those boys couldn't have had a better mom. She worked, she took care of them," Sylvia Greenway said.
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