WILLIAMSON COUNTY, Texas (KXAN) — A 21-year-old mother was arrested after her 1-year-old drowned in a Round Rock apartment bathtub in January, according to an arrest affidavit.

Victoria Tristan, 21, was charged with injury to a child, a first-degree felony, after she fell asleep for approximately 10 minutes, leaving the child unattended in the bathtub, the affidavit said.

An attorney for Tristan wasn’t available at the time of this report. KXAN will update this story if that information becomes available.

Tristan told officers she placed the child in the tub and washed her off with the water running. A few minutes later, Tristan walked away, sat on a bed and began texting with a family member. Then, she leaned over to rest her head, falling asleep for a few minutes, the affidavit said.

When she woke up, Tristan said she went straight to the bathroom, where the bathtub was full of water. Tristan removed the child from the tub and attempted CPR, but the child wasn’t responsive, the document said.

According to the affidavit, cell phone data showed Tristan texting for five minutes before an eight-minute gap in activity. Then, Tristan searched YouTube before calling 911 four minutes later. The first officer arrived at the apartment three minutes later.

The Travis County Medical Examiner decided the cause of death was drowning and ruled it an accident, the affidavit said.

The affidavit said Tristan knowingly, by omission, caused serious bodily injury when she left the child unattended in the bath.

Tristan is in custody at Williamson County jail as of Thursday night.