Millbrae Middle School teacher Heather Butts pleaded not guilty to felony charges among them committing a lewd act with a child.
San Mateo County District Attorney Steve Wagstaffe calls this a case where a teacher who is 25-years-older than the student, took advantage of her.
RELATED: Sheriff's office, school district may have known of Millbrae teacher-student relationship
The case became even more complicated when ABC7 News learned that the Sheriff's investigators in Millbrae knew about the relationship as far back as last fall, but did nothing.
Millbrae teacher Heather Butts pleads not guilty today to committing lewd acts with a minor. Her lawyer says it's a complicated case. pic.twitter.com/qG9Oski0S4— Vic Lee (@vicleeabc7) September 19, 2016
"It's complicated. It's a very complicated situation in a very complicated case," said Paula Canny, Butts lawyer.
ABC7 News is not naming the girl who has since graduated from Taylor Middle School, where Butts teaches.
Butts was arrested last month after police found her with the girl in a parked car on Santa Helena Avenue in San Bruno.
RELATED: Millbrae teacher accused of having inappropriate relationship with teen
ABC7 News has also learned that a school parent went to Millbrae police as far back as last October and filed a police report after he heard about the illicit relationship.
But the Sheriff's Office, which staffs the Millbrae Police Department, apparently failed to investigate.
Then, in February, that same parent went to the high school where the victim now attends and told an administrator the same story.
The school district called the Sheriff's Office but again, they failed to act.
San Mateo County Sheriff Carlos Bolanos has launched an internal investigation.
"Clearly, we do believe a breakdown did occur. It is not the type of service we try to provide to our residents and we're very sorry about that," said Bolanos.
The Millbrae School District has suspended Butts while it conducts its own investigation.