ALVIN, Texas -

The Alvin Independent School District says a staff member is under investigation for having an alleged inappropriate relationship with a student.

School officials found out about the accusations after getting an anonymous tip on the school district's smart phone app.

At Alvin High School there's a murmur among the 2,400 students who attend about an alleged relationship between employee and a student. With a letter going out today, parents now know too.

The tipster said that during the summer, a female staff member from Alvin High School was involved with an 18-year-old male student.

Local 2 has learned the female staff member, who is not a teacher, has now resigned but hasn't been charged with a crime at this point.

Alvin High School has had similar trouble before.

Earlier this year, two other Alvin employees - a coach and a teacher - were arrested. One for an inappropriate relationship and the other for possession of child pornography.