A former Kingwood high school teacher is now facing charges, accused of having sex with a female student.

Zachary Harlan was a social studies teacher, as well as a boys soccer and junior varsity football coach, at Kingwood Park High School when he was placed on administrative leave back in November after allegations of an inappropriate relationship with a student.

Harlan, 35, resigned the next week. He had been with Humble ISD since 2004.

A subsequent investigation led to charge of improper relationship with a student against Harlan.

Court documents state the principal at the high school received an anonymous call about the relationship. Both the victim -- a 17-year-old senior -- and Harlan gave written statements to the principal.

According to court documents, Harlan wrote, "Our conversations and emails began to become flirtatious and then inappropriate... I allowed her to become attached to me on a personal level and I allowed myself to do the same... I allowed it to go too far."

The emails between Harlan and the girl started in Sept. 2013 and continued through Nov. 2013. Investigators say the emails showed that a sexual relationship was taking place.

Harlan posted a $10,000 bond. He's due back in court on Feb. 14.

Humble ISD released a statement Friday which read in part: "Humble ISD has zero-tolerance for inappropriate relationships between teachers and students. The district cooperates with law enforcement for the safety and welfare of our students."