SUN PRAIRIE, Wis. -

A Sun Prairie High School employee denies knowing the boy she is accused of having inappropriate contact with was a minor, according to a criminal complaint.

The 25-year-old was fired from Sun Prairie High School, where she worked as a special education teacher's aide, after she was accused of inappropriate contact with the boy, officials said.

Kula admitted to having a relationship with a younger man that told her he was 18 years old, according to the complaint. Kula told police she met the man at a McDonald's and didn't learn he was a student at the high school until after they had sexual contact.

The teenage boy told police he met Kula at the school, they started flirting, and she sent him a friend request on Facebook, according to the complaint. The teenager told police he never told Kula he was 18, and that they talked about him not being 18 yet.

The Sun Prairie Police Department said Kula was taken into custody Friday on a charge of sexual assault of a child by a school staff person.

Bond for Kula has been set at $500, and she was ordered not to have any contact with the teenager or be on schools grounds. She faces a $10,000 fine, up to six years in prison or both if found guilty.