A former Joplin teacher pleaded guilty in federal court Tuesday to charges related to enticing one of her students to engage in illicit sex.

Amanda Ruth Schweitzer, 41, was a teacher at North Middle School in Joplin at the time of the offense, according to a statement from the U.S. Attorney's Office for the Western District of Missouri. 

The plea agreement appears to dismiss a second count of transferring obscene material to a minor.

The 13-year-old victim, who was a student of Schweitzer’s, reported Schweitzer sent nude photos of herself to the victim, with whom she primarily communicated via Instagram, and engaged in sexual intercourse with the victim on at least two occasions in March 2017. The victim reported that he also sent a nude image of himself to Schweitzer.

Schweitzer is subject to a mandatory minimum sentence of 10 years in federal prison without parole, up to a sentence of life in federal prison without parole.

A sentencing hearing will be scheduled after the completion of a presentencing investigation by the United States Probation Office.

Schweitzer is also still facing a charge in Jasper County Circuit Court of statutory rape of a 13-year-old male student, and in Newton County Circuit Court with kidnapping, statutory rape and statutory sodomy involving the same boy.

A Joplin police investigation of Schweitzer began in 2017 when police were informed of allegations that she sent nude images of herself to three North Middle School boys.

Police reports obtained by the Globe state that the school principal was contacted by the mother of two of the boys and the mother of the third concerning photos sent to their sons via Instagram.

According to one report, the mothers informed the principal that their sons told them about the photos, which had been deleted by the time they learned of them and checked their sons' phones.

The allegations were reported to the state's child abuse hotline and interviews of the boys were set up at the Children's Center in Joplin.

The mother of two of the boys brought them to the center for interviews and informed a detective that one of her sons had disclosed to her that he engaged in sexual intercourse with Schweitzer the previous day. She gave the detective a bag containing the boy's shorts and told him that she had not allowed her son to bathe prior to any examination that might be needed.

The boy who made the disclosure told investigators during his interview that Schweitzer began sending text messages to him several weeks earlier.

"She told him that he was hot and that she wanted him," the detective wrote in the report.

He primarily communicated with her using the Instagram app on his phone, the boy told investigators. She had sent him photographs of her breasts and other nude photos of herself in the past, including one involving a sex toy, according to the report. She also asked him to send her photos of himself, he told investigators.

The week preceding the week of the interview, it was spring break and Schweitzer had taken him "to the river" in her car, and they had sex for the first time, the boy told investigators. She was intoxicated and offered him some of her drink, but he refused, the boy told investigators.

She then touched him and performed a sex act on him followed by intercourse, the boy told investigators. Afterward, he asked her to take him home and she dropped him off a couple of blocks from his house.

The boy told investigators that he believes that they were somewhere near Diamond that first time. He recalled there being "a bar under caves," a detail of the police report that lines up with the probable-cause affidavit in the Newton County case, which names a campground south of Joplin.

A supplemental report in the police investigation indicates that a possible corroborating witness came forward in April to state that he recognized Schweitzer in images on local news coverage as a woman he encountered in the campground, although he could not recall the exact date.

He said he came upon Schweitzer in the company of a boy he took to be her son. He thought she looked familiar then and told her that. She told him that her family often used the campground and that she worked at North Middle School in Joplin.

The witness told police that he could smell alcohol in the cup the woman had in her hand and thought it odd that she would be drinking in the presence of her son.

The boy told investigators that the second time they had sex had been the day before the interview. He had not gone to school and was at a relative's home when she text messaged him asking why he was not at school. She then came by, picked him up and took him to her house, where they again had intercourse.

The boy told investigators that there was a blue-and-white blanket with a floral pattern on the bed. When police served a search warrant on Schweitzer's residence the day of the boy's interview, a blue-and-white comforter was found in the dryer, according to another supplemental police report.

Andy Ostmeyer is the metro editor at the Globe. His email address is aostmeyer@joplinglobe.com.