A Texas high school teacher accused of having sex with a 15-year-old student allegedly texted him about “car sex,” saying she had “fun in the back seat,” PEOPLE confirms.

Erica Dinora Gomez, 23, of Austin, was booked into the Travis County Jail Monday and charged with sexual assault of a child and an improper relationship between an educator and a student, both second-degree felonies, according to an arrest affidavit obtained by PEOPLE.

The allegations came to light on Sunday, when the boy’s mother called 911 saying she wanted to report the alleged sexual assault of her son, the affidavit states.

The mom told police she searched her son’s phone when he came home at 6:30 a.m. and she found him lying on top of his bed, fully clothed, the affidavit states. She told police she found several explicit Snapchat messages from someone with the screen name “Special” — whose real username she soon learned was “Ericadinora,” the affidavit states.

In the messages, Gomez allegedly wrote, “Babe… We’ve had car sex twice… Like that blows my mind LOL,” the affidavit states.

In another message, the affidavit states, Gomez allegedly wrote that “every time she gets into her vehicle, she is reminded of what ‘fun in the back seat’ that she and the juvenile victim had.”

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Searching Facebook for clues to the username’s identity, the mother “immediately recognized ‘Ericadinora’ as a former math tutor for her 15-year-old son,” the affidavit states.

Gomez is also a teacher at Bowie High School, where the alleged victim is a student, the affidavit states. According to her Facebook page, she graduated from the University of Texas in 2017.

During police questioning, Gomez allegedly confessed to the sexual relationship, the affidavit states. She allegedly said she met the boy in January and began having sex with him in August, after which they had sex four to five times.

Bowie Principal Mark Robinson sent a letter to parents on Monday night about the arrest, announcing Gomez was terminated, the Austin American-Statesman reports.

“Based on the most recent information obtained, the district is taking action to terminate her employment and, as required by law, is reporting the incident to the Texas Education Agency,” Robinson said.

Gomez remains held at the county jail on $75,000 bail, jail records show. If convicted, she faces up to 20 years in prison and a maximum fine of $10,000.

It is unclear whether Gomez has retained an attorney who can comment on her behalf.