Court documents released on Tuesday detailed the murder and suspects.
Jeremy Goodale and Willard Miller, both 16 years old, are accused of killing Nohema Graber, 66. Ms Graber taught them Spanish at Fairfield High School, approximately 95 miles southwest of Des Moines.
Both teens are being charged as adults with first-degree murder.
Fox News reports that the woman's body was found buried under a tarp, a wheelbarrow and some railroad ties at a local park the day after she went missing.
According to the court documents, Mr Goodale allegedly wrote messages on Snapchat detailing how he and Mr Miller stalked Ms Graber before killing her with the bat. He also documented where they hid the body and how they disposed of the evidence.
Those documents were unsealed by a judge earlier this week.
According to the court documents, someone who knew Mr Goodale saw the messages that showed the teens "were involved in the planning, execution, and disposal of evidence" in her killing and shared them with authorities.
Mr Miller was questioned by the Iowa Division of Criminal Investigations and claimed he brought the wheelbarrow from his house.
On the day of the killing, Ms Graber entered the park where her body was found on 2 November, leaving her car in the parking lot. The car left the lot about 42 minutes later followed by a truck. Her body was found in the park the next day.
The lawyers representing the teens attempted to have a judge bar the media and public from their trial, but a judge denied that request, arguing that the attorneys failed to show that the teens' trial would be irreparably damaged if it was open to the public.
No motive for the crime has been released as of Thursday.
First-degree murder charges in Iowa carry a life sentence, though a 2016 Iowa Supreme Court judgement banned the imposition of life sentences without parole for offenders under the age of 18, calling it cruel and unusual punishment under the state constitution.
If the teens were tried as minors they would be eligible for release from prison at age 18, serving only two years for the killing. If they are tried as adults and convicted, they will likely serve lengthy prison sentences.