A pair of Iowa teens charged in the brutal killing of their Spanish high school teacher pleaded guilty to first-degree murder on Tuesday.

Willard Miller, 17, and Jeremy Goodale, 18, changed their pleas to guilty and admitted helping kill beloved Fairfield High School teacher Nohema Graber in late 2021.

The teens, who were charged as adults because of the severity of the crime, had previously pleaded not guilty to charges of first-degree murder and conspiracy to commit murder.

Graber was reported missing on Nov. 2, 2021. Her body was found the following day hidden under a tarp, wheelbarrow and railroad ties at a park in Fairfield, a small town of 9,500 people around 100 miles southeast of Des Moines.

Investigators say the teens, who were 16 at the time, used a baseball bat to fatally beat their 66-year-old teacher.

She was allegedly killed for revenge over a bad grade, according to court documents.

Prosecutors say the investigation shows the two boys struck their teacher with a bat.

Miller denies ever hitting Graber but admitted to helping plan and carry out the attack. He reportedly described to investigators the frustrations he had with the way the teacher taught Spanish, and also how his grade in Spanish was lowering his overall GPA.

“The poor grade is believed to be the motive behind the murder of Graber which directly connects Miller,” court documents filed by Jefferson County Attorney Chauncey Moulding and Assistant Iowa Attorney General Scott Brown said.

Goodale had previously agreed to testify against Miller, whose trial was expected to begin this week.

As part of the plea deal, prosecutors agreed to recommend a sentence between 30 years and life in prison for Miller, with the possibility of parole, for Miller; and between 25 years and life in prison, with the possibility of parole, for Goodale.

With News Wire Services