TROPHY CLUB, Texas – Police believe pregnant Texas middle school teacher Katherine Ruth Harper’s relationship with a 15-year-old student evolved from exchanging nude pictures to multiple sex romps last summer.

Harper, a 27-year-old English teacher at Tidwell Middle School in Roanoke, was charged with improper relationship between an educator and student last week after a three month long investigation confirmed her affair with the seventh-grader, the Star-Telegram reports.

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Harper, also a cheerleader and tennis coach at the school, allegedly began exchanging flirty text messages with the student last year, leading Harper to hook up with the boy at his home in Trophy Club during the summer break.

According to the news site:

In an interview with a state Child Protective Services investigator, the teen said he and Harper began drinking alcohol and both took off their clothes. At that time, the teen performed a sex act on Harper, according to the affidavit.

After that, the two had sex several times either at his home or hers from June 1, 2016, to July 31, 2016.

The two communicated with each other about 76 times during that time, based on their cellphone records, according to the affidavit.

Harper and the student exchanged nude images in those messages, which were saved by the student on his cell phone and turned over to police, according to investigators.

School officials initially launched an investigation after receiving a tip about the relationship in September 2016, but could not identify the student involved and closed the investigation.

Another tip provided more details in December, when school officials suspended Harper and launched another investigation, Fox 4 reports.

Police allege the teen broke down in tears and admitted to having sex with Harper when confronted by a school official.

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It’s unclear whether Harper’s pregnancy is a result of the relationship.

The teacher was arrested for the second-degree felony on March 21 and booked into Denton County Jail. She was later released on a $15,000 bond, according to a prepared statement from the Trophy Club Police Department.

Harper’s arrest is only the latest in an epidemic of educators sexually abusing students. She was one of two Texas teachers arrested on the same day for alleged sex with students.

Rebecca Goerdel, a special education teacher at the all-boys Young Men’s Leadership Academy in the Grand Prairie Independent School District has also been on leave since officials learned of her alleged relationship with a student March 10, according to WFAA.

“This kind of conduct is outrageous and will not be tolerated,” Grand Prairie superintendent Susan Hull said in a prepared statement. “The teacher-student relationship is sacred. It reflects a vow from teachers to parents that their children are safe – as safe as they would be at home.

“When a teacher in Grand Prairie ISD breaks that vow, he or she will be dealt with quickly and aggressively,” she said.

Texas lawmakers are currently considering legislation to crack down on student-teacher sex cases.

Figures from the Texas Education Agency, the state agency tasked with investigating teacher misconduct, show a total of 686 teachers have lost or surrendered their licenses because of improper relationships with students between January 2010 and December 2016, the Austin Statesman reports.