Jon Lilly faces charges of possessing sexually explicit photos of a minor.
Lilly taught at Morton High School in Hammond.
He's in jail tonight and is expected to face a judge Friday.
A mother's discusses her sadness after her daughter, who turned 18 a week ago, moved out claiming she loved Lilly, a former Morton High School math teacher.
"It is so devastating," the mother said. "I would never wish this on anybody's family."
"I know by me going through - me and my husband - going through with the charges. We've lost our daughter right now," she said.
The mother says she learned about the sexual relationship early February, when she met with school officials and police.
"They asked us a stupid, stupid question - do you want to press charges? I said - "hell yes, yes we're pressing charges," she said.
The mother says, the school did not tell her what court records revealed:
"One administrator explained that she had written Lilly up in November due to an incident in his classroom. She explained that Jane Doe 1 was discovered sitting between Lilly's legs," she said.
The mother says Jane Doe 1 is her daughter.
"He should have been gone that day in November," the mother said.
According to court records:
Jane Doe 1 admitted to having a sexual relationship with Lilly.
Lilly had hundreds of explicit photos of Jane Doe 1 and heconvinced at least 3 other students to text or send partially clad photos to him.
"I hate him," the mother said. "Hate is a strong word."
The school district's statement says: "The School City of Hammond has been and will continue to cooperate with law enforcement in its investigation into the conduct of this teacher."
This mother is reaching out to other parents.
"The more people who will come forward, the longer this scumbag will spend in prison," the mother said.