(Fairfield IA) -- The two teenagers accused of killing their teacher in southeast Iowa will go to trial on murder charges in the spring. Sixteen-year-olds Jeremy Goodale and Willard Miller have both pleaded not guilty to first-degree murder. They're accused of murdering Fairfield High School Spanish teacher Nohema Graber earlier this month. Her body was found hidden in a park in Fairfield the day after she was reported missing. Police investigators say they know what the motive was but it hasn't been released. After the teens appeared in court the Jefferson County attorney's office says a jury trial is tentatively set for April 19th. The judge in the case is still considering a request to lower the teens' bonds. They're currently in jail on one-million dollars bond each.