A Texas science teacher has been accused of a conducting a year-long sexual relationship with a former student. Kristina Lynn Moore, 48, of Katy, who was a teacher at Thornton Middle School in Cypress-Fairbanks is charged with sexual assault of a child during the alleged relationship. The student, who was 14 at the time, has now moved onto high school and is no longer at the school. The two allegedly began seeing each other in February 2013 when the student told investigators he asked Moore for her number and she gave it to him. They began text messaging which allegedly escalated into to a sexual encounter. School district records show Moore called in sick to school on the day the alleged affair began. Authorities were told that the two had a number of sexual encounters at his home, Moore's home, the school and at a deserted area of a dead end roadway near a neighboring elementary school. The relationship allegedly ended in April of this year. Investigators say the student turned over a Valentine's card he claims is from Moore, which reads 'You've got this Kat on lockdown...LOL! You always make my 3 wishes come true, ? you, you know who this is...LOL.' The alleged relationship was exposed after a neighboring teacher observed suspicious activity. The teacher and student were then interviewed by authorities at the same time but in different interview rooms. Moore denies the relationship. Assistant Superintendent Nicole Ray issued a statement saying: 'The teacher in question was removed from campus immediately when the allegations were made and is no longer an employee of the district. We are extremely concerned by the seriousness of the charges and will continue to cooperate with law enforcement. The safety of our students is our number one priority; inappropriate behavior will not be tolerated.'