A Frederick County Public Schools gym teacher and a teacher's aide were arrested Thursday in unrelated incidents involving alleged sexual or inappropriate contact with students, according to the Frederick County Sheriff's Office.

This is the third such arrest of a Frederick County Public Schools employee this year.

Emily Shay Walker, 23, a physical education teacher and basketball coach at Frederick County Middle School, has been charged with a felony count of indecent liberties with a child following an investigation launched last week by the Sheriff's Office. She was booked at the Northwestern Regional Adult Detention Center on Thursday after voluntarily turning herself in.

"It has been alleged that Walker had inappropriate contact with a 12-year-old student on more than one occasion," a media release from the Sheriff's Office states. "Evidence of hundreds of text messages exchanged between Walker and the student, over the course of several weeks, indicated an escalation in expectations of physical contact."

The male victim, who has since turned 13, "also met Walker, on more than one occasion, on school property where the two are alleged to have kissed," the release states.

Matthew Jurgen Geyer, 41, a teacher's aide at Sherando High School, has been charged with a misdemeanor count of contributing to the delinquency of a minor following an investigation that also began last week. He is alleged to have had a "consensual sexual encounter" with a 16-year-old male student "after the two met through a social media app a few months ago. This investigation has confirmed that Geyer and the victim met off school property, at the victim's home, where sexual contact was made between the two."

Geyer is being held at the Northwestern Regional Detention Center without bond, according to the release.

School families and staff were notified last week in letters from their respective principals about the allegations and that the employees had been placed on administrative leave.

"This morning, I became aware that one of our teachers and a student may have engaged in an inappropriate relationship," Frederick County Middle School Principal Jerry Putt wrote in a March 13 letter. "Both law enforcement and school division staff are following established procedures to investigate the matter and take appropriate action in accordance with the Code of Virginia and school division policy."

A March 15 letter from Sherando High School Principal John Nelson stated that, "This morning, I became aware that one of our staff members and a student may have had inappropriate sexual contact outside of the school."

On Jan. 26, James Wood High School Principal Sam Gross informed school families and staff that he had been made aware that a substitute teacher may have had "inappropriate sexual contact" with a student at school.

Since then, Kyle Ray Hendrickson, 37, has been indicted on two felony counts of indecent liberties with a minor while in a custodial role. He is accused of touching a juvenile to perform an act of fellatio, according to court documents. His employment with the school division was terminated on Jan. 25, schools officials have said. His next court date is April 28.

In the wake of the alleged incidents, Frederick County Public Schools Superintendent George Hummer last week sent a letter to school families calling the situation "completely unacceptable." He said the school division would be "taking a number of actions to reiterate to all staff the importance of complying with our policies, particularly those that detail the high expectations we have for staff interactions with students." He cited division policy that states "all staff members are expected to maintain professional boundaries with students and serve as a role model at all times."

Hummer encouraged anyone with a concern about a relationship or activities between a staff member and a student to immediately bring it to the attention of their school principal or another staff member.

Frederick County Public Schools has 19 schools and serves more than 14,000 students.