MINNEAPOLIS (WCCO) – A former Catholic school teacher from southern Minnesota faces six felony charges after police say she admitted to having sex several times with a 17-year-old student.

Mary Frances Gilles, of Austin, faces six counts of third-degree criminal sexual conduct. Each charge carries a maximum penalty of 15 years in prison and/or a $30,000 fine.

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Gilles, 28, was a math teacher at Pacelli High School. She was fired from her job Tuesday after police arrested her a day earlier.

According to a criminal complaint, police were called to the school Monday after suspicions arose that Gilles was having sex with a student. A school administrator told police she’d seen emails between Gilles and the student, and their contents were sexual in nature.

The administrator told police she saw the emails after she began looking at the student’s school account when she got a “gut feeling” something was wrong. While she didn’t find anything suspicious in the student’s school email, she did find a password for another account. She then accessed that account and found correspondence with Gilles that was sexual in nature.

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Police say an officer looked at the emails, one of which spoke of Gilles possibly being pregnant.

An investigator met with the student, the complaint states. In an interview, the student said he had a close relationship with Gilles and had been having sex with her since February. He said they first had sex at her house and that they’d had intercourse about seven times in total.

Police also interviewed Gilles. She admitted to investigators that her relationship with the student began in February or March and that they had sex about once a month since then. She said she knew the student was 17.

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Gilles is being held on $100,000 bail.