Authorities say a 14-year-old died in the Friday crash, and in the video, Sanchez references the victim as her sister. The CHP says the two minors in the back seat were not wearing seat belts.
The CHP says Sanchez was under the influence when she rolled her car over into a barbed wire fence and then into a field.
Merced County Sheriff Vern Warnke said 14-year-old Jacqueline Sanchez was killed in the crash near Henry Miller Road and Highway 165, and another 14-year-old girl was badly injured.
"She was in the back seat of the vehicle and allegedly unseatbelted, and upon the vehicle rolling over, it ejected her and killed her," Warnke said.
"I f------ killed my sister. I know I'm going to jail for life, I understand that," Sanchez says in the video. "I don't give a f---."
Sanchez then yells for her sister to "wake up."
"This is the last thing I wanted to happen to us, but it just did...I don't f------ care, though. I'm a hold it down."
Mary Hernandez of Stockton recorded the livestream.
"At first, we didn't even want to believe it was real," she said. "I recorded it and posted it mainly because as someone who uses Snapchat, I see a lot of people driving with their Snapchats doing what she was doing. So to me, it was like an eye opener."
Family members confirmed that Obdulia Sanchez filmed the video before, during and after the crash that was posted on Instagram.
They said Jacqueline was supposed to celebrate her quinceanera on Sunday.
Sanchez is now in the Merced County Jail on charges of vehicular manslaughter while under the influence and DUI.
Family members started a GoFundMe page for Jacqueline's funeral expenses.
Photos of the scene courtesy of Merced Sun Star