DENVER -- After almost two full days of deliberation, a Jefferson County jury returned a split verdict Tuesday in the case of a former Dakota Ridge High School teacher and tennis coach accused of having sex with a student when she was 17 years old.

Kevin Ponis, 36, was found not guilty of sexual assault on a child, but guilty on sexual assault on a child by a person in a position of trust. The jury could not reach a unanimous decision on the eight other charges he faced. Prosecutors said they have no plans to pursue those charges in a second trial.

Ponis admitted he had a sexual relationship with a student and a member of the tennis team, but testified that he thought the student was 18, because she told him she was, and that the relationship was consensual.

The teenager testified last week that she had developed a crush on Ponis, and looked up to him and during one point, he had told her, "Think of me as a big brother. I will always be there for you."

The victim's mother said she was pleased with the verdict and had a message for Ponis.

"I knew all along that this was happening and I'm so glad you took it far enough to get caught, because you deserve it," she told reporters.

Testimony during his trial revealed that the former tennis coach had sex with at least two other students, who were 18 years old, and the sex was therefore not a crime.

The jury got the case late Monday and had deliberated all day Monday and part of Tuesday before finally reaching a verdict.

The guilty verdict on the count of sexual assault on a child by a person of trust carries mandatory jail time of eight years, minimum. The maximum sentence could be 24 years in prison.

Ponis was taken into custody as soon as the verdict was announced. He'll be formally sentenced on March 8.