The older sister of the 15-year-old boy who was allegedly sexually molested by his fifth grade teacher talks to News 8.

We're not identifying the victim's older sister or his mother, who spoke openly about the suspect.

"She fooled me. She used me to get to my brother. We never thought anything was wrong about her. We saw her as a good person,"

Feistel befriended the young woman and moved into the family's home for several months. That's when she apparently became more than just friends with the girl's younger sibling, who had also been a student in Feistel's fifth grade class at Rosa Parks Elementary School two years earlier.

"I want to know why she did what she did," the young woman said.

Adrienne Feistel has pleaded not guilty to 10 felony counts of performing sex acts on the now 15-year-old boy, who was 13 when the alleged activity began.

"She would always want to stay up, going into the living room, started drinking... she'd want to go to my brother's room when he was sleeping," the young woman said.

That behavior eventually caught the attention of the boy's mother.

"In the morning my mom told me 'Where's Adrienne?' I said she was here sleeping, she probably left. No, she was in bed with my brother," the young woman said.

Investigators say the sex acts happened between the summer of 2006 and lasted until August 2008. That's also when authorities learned about the improper relationship between the boy and Feistel, who is married to a deputy sheriff and who has a young son.

"There's proof that she did. I mean, we know it happened. We know it's true," the young woman said.

The victim's loved ones say his personality has dramatically changed.

"He was calm, he had good grades in school. He wouldn't yell. He's different now. His grades are lower, he yells, he's aggressive," the young woman said.

The young man's relatives strongly believe he may not be Adrienne Feistel's only victim.

"If she ever did this to anyone else, please say the truth. Put themselves in our shoes and feel the pain we're feeling. Call the police and say the truth," the young woman said.

News 8 spoke to Adrienne Feistel's mother, who says there's definitely a second side to this story, and her daughter is in the process of getting a lawyer.

Feistel is free on $50,000 bail.