Madras High School track coach Melissa Bowerman sent naked photos of herself to a student on her team, exchanged sexual messages and asked the 17-year-old if he wanted to have sex with her, according to a probable cause affidavit filed in Jefferson County Circuit Court.

The 43-year-old woman, who is the daughter-in-law of the late Nike co-founder Bill Bowerman, also kissed the teen, smacked him on the buttocks and asked him to send her a photo of his genitals, according to the filing from Oregon State Police Det. James Koehler narrating the teen's account.

Bowerman was arrested Monday at her home in Fossil and has been charged with using a child in a display of sexually explicit conduct, second-degree sex abuse and luring a minor. A grand jury issued an indictment Wednesday and she is scheduled to be arraigned Friday in Jefferson County Circuit Court. The charges concern alleged abuse from May to June.

She is being held in the Jefferson County jail on $50,000 bail, said Jefferson County District Attorney Steven Leriche.

Her court-appointed attorney, Jennifer Kimble, said Wednesday that Bowerman "appreciates everyone respecting her and her family's privacy at this difficult time."

According to the affidavit obtained by The Oregonian, a relative of Bowerman alerted police in early July that she might be having a sexual relationship with a student. The relative provided authorities with Facebook messages in which Bowerman said the teen, whom she referred to as her "monkey boy," had promised to love her but then dumped her. She said she loved him, referring to herself as his "angel girl," and sent a photo of herself wearing his track jersey with a monkey patch sewn onto it, the filing states.

The teen was interviewed by police about nine days later. He said Bowerman's conversations with him over social media were at first general, but they turned sexual, the affidavit states. He told police the coach gave him the track jersey with the monkey on it during the season. She then sent him the naked photos of herself, he told police, and asked him to masturbate. When she asked for a photo of his genitals, he sent her a photo from the Internet, pretending it was his, the affidavit says.

The teen said when Bowerman asked if he wanted to have sex, that he told her no, the detective wrote in the affidavit, and the student recalled she made reference to having to wait until he turned 18. The teen said Bowerman drove him home after an awards banquet and at some point he rubbed her stomach and grabbed her breast, which she smiled at, the affidavit states.

At the end of the track season, the teen said he willingly kissed Bowerman in the locker room and kissed her again on the lips at her request, the filing states, adding that she then smacked him on the buttocks as they left.

Police interviewed Bowerman on Monday. The coach at that time alleged the teen had kissed her against her will, the affidavit states, and that he forcibly put his hand down her pants and forced her to put her hand down his pants. Under questioning, she admitted sending photos of herself and asking for naked photos of the teen, and that she had talked with him about meeting for sex, the affidavit states.

Officers searching her home found the teen's track jersey and a comforter that appeared in the naked photos.

Melissa Bowerman has been married to Jon Bowerman, 76, the son of the late Nike co-founder, for six years.

Melissa Bowerman's conduct drew attention in May 2012, when she was dismissed as the volunteer Condon/Wheeler track coach after escorting a 17-year-old boy to the Condon High School prom. She had been coaching the team with her husband.

At the time, Brad Sperry, athletic director of Wheeler High School and superintendent of the Fossil School District, told The Oregonian: "All I will say for the record is that there is way more to that story than just a date to the prom and no comment on anything else. It's very unfortunate it ever got to this point. ... A thing like this, there's two sides. One side normally talks, and the other can't talk."

Gilliam County Sheriff Gary Bettencourt, who received a complaint from a chaperone, said he has found no evidence that Bowerman broke the law.

Bowerman said attending the prom with a boy from the track team was an error in judgment, but she felt bad because he didn't have a date and was struggling in English class. She said the two did not have an inappropriate relationship.

-- Helen Jung