The documents reveal a possible motive in the case for the first time since the teenagers — Willard Miller and Jeremy Goodale — were arrested in November 2021. The boys, then 16, face murder charges in the death of the 66-year-old former teacher Nohema Graber. According to investigators, Miller had met with Graber on Nov. 2, 2021, to discuss his poor grade in her class. The teacher drove later that day to a park where he was known to take daily walks after school. Witnesses reported seeing her van leave the park less than an hour after she arrived with two men in the front seat. The van was left at the end of a rural road and a witness later picked up the two boys as they walked towards town on the same road, investigators said. SUSPECT WHO FLED IOWA OFFICERS DIES AFTER SHOOT EXCHANGE Willard Miller (left) and Jeremy Everett Goodale (right) in court. (Associated Press) Graeber’s body was found in the park the next day under a tarp, cart and railroad ties. She had been beaten to death with a baseball bat, according to investigators, and one of the teenagers bragged about the incident on social media. In speaking to police, Miller said he was frustrated with Graber’s teaching methods and how his grade in her class was lowering his GPA. “A bad grade is believed to be the motive behind Graeber’s killing which directly links Miller,” said court documents filed by Jefferson County District Attorney Chauncey Molding and Iowa Assistant Attorney General Scott Brown. Miller initially denied involvement in his teacher’s death, but later said he was aware of the events but not involved, and that a “roving group of masked kids” were the real killers, forcing him to give them his stroller to help move her body. He also claimed the allegedly masked kids made him drive her van out of the park, according to court documents. IOWA MAN SAVES 4 BROTHERS FROM RAGING INFERNO AFTER TAKES WRONG TURN: ‘LIVES HAVE BEEN SAVED HERE’ The two teenagers face murder charges in the death of their 66-year-old teacher Nohema Graber. (Fairfield Iowa Police Department via AP) A witness provided investigators with photos of a Snapchat conversation with Goodale that revealed “Goodale’s admissions that he acted in concert with another person to cause Graber’s death.” The witness said Goodale made comments implicating himself and Miller by name. But Miller’s attorney, Christine Branstad, claims four search warrants were issued illegally, in part because “law enforcement failed to provide information to the issuing judge to show that the informant is credible or that the information from the informant should to be considered reliable”. Two Iowa high school students killed their Spanish teacher last year in retaliation for receiving a bad grade, prosecutors said in court documents Tuesday. (Fairfield Police Department via AP) CLICK HERE TO GET THE FOX NEWS APP Branstad is asking the court to quash all four search warrants and suppress evidence from Miller’s home, comments he made to police and information obtained from his cellphone and Snapchat. Miller is scheduled to be arraigned on March 20, and Goodale’s trial is set for Dec. 5. The teenagers, both 17, will be tried as adults. The Associated Press contributed to this report.