A Massachusetts teenager 's confession to police that he killed his math teacher can not be used in his murder trial , a judge ruled Tuesday even as he allowed a bloody box cutter and other key pieces of evidence to be admitted . The ruling came in the case of 16-year-old Philip Chism , who has pleaded not guilty to raping and killing 24-year-old Danvers High School teacher Colleen Ritzer on school grounds in October 2013 . Chism 's lawyers had argued that police coerced their client , then 14 , into making detailed statements about the killing , despite invoking his right to remain silent . Prosecutors maintained Chism and his mother had never absolutely demanded a lawyer . Scroll down for video . Confession not admissible : Philip Chism - seen here in a Massachusetts court in January - confessed to police that he killed his math teacher , however a judge has ruled it can not be used in his murder trial . Essex County District Attorney Jonathan Blodgett , through a spokeswoman , said his office was still reviewing the decision . Calls to Chism 's public defenders seeking comment were not immediately returned . Ritzer 's family said in a statement it respected the court ruling and was confident that law enforcement 'acted responsibly and lawfully ' in investigating their daughter 's killing . The 48-page decision came after days of arguments and testimony on the defense 's motion to suppress key pieces of evidence in the case . Salem Superior Court Judge David Lowy concluded that Chism had willingly talked to police in the town of Topsfield on the night of the killing , calmly answering questions and even correcting officers at various points . But Chism 's demeanor changed when he was taken to the Danvers police station and further interrogated in his mother 's presence , the judge noted . At that point , Lowy said , Chism grew uncomfortable and somewhat hostile . Murdered : Colleen Ritzer was a popular and enthusiastic math teacher at Danvers High School . Phillip Chism has pleaded not guilty to her rape and murder . Charged : Philip D. Chism was indicted by an Essex County grand jury today on charges of first-degree murder , aggravated rape and armed robbery in 2013 . He twice indicated his disinterest in speaking with Danvers police and 'did not appear to be fully engaged ' or to appreciate the seriousness of what officers asked him as they explained his Miranda rights , the judge wrote . 'It is clear that the defendant wanted to talk to the police without his mother present in the room , ' Lowy said in his ruling . 'It is also clear that he had no intention of talking while his mother was in the room . ' As a result , the judge said , he would allow the statements Chism made to Topsfield police to be introduced as evidence but not his taped confession at the Danvers police station . He also allowed items gathered at Danvers High School , as well as those seized from Chism 's pockets and backpack . They included Ritzer 's ID and credit cards , a bloody box cutter and women 's underwear . In memoriam : The campus of Danvers High School was flooded with flowers and other tokens following the October 2013 murder of teacher Colleen Ritzer . R.I.P . : Danvers High School community mourns the tragic death of beloved math teacher Colleen Ritzer whose body was found behind the school . But Lowy ruled prosecutors can not use evidence from Chism 's and Ritzer 's cellphones , which were found near a movie complex . Authorities say surveillance video from October 22 , 2013 , shows Chism following Ritzer into a school bathroom , wearing gloves and a hood , then later walking out of the bathroom alone . A short time later , the video shows Chism pulling a recycling barrel through the school and outside . Ritzer 's body was later found in nearby woods , naked from the waist down and with her throat slit and a note that read , ' I hate you all . ' Authorities said she was sexually assaulted with a stick . A bloody recycling bin was found nearby . Dianna Chism ( left ) attends her son Philip Chism 's hearing in Suffolk County Juvenile Court Wednesday , July 23 , 2013 , in Boston , where he was arraigned for allegedly assaulting a state worker while he was in custody at a Department of Youth Services facility . Chism , who had recently moved to Massachusetts from Clarksville , Tennessee , was found that night by Topsfield police walking along a nearby highway . Prosecutors allege that after the killing , Chism used Ritzer 's credit card to buy fast food and attend a movie at the mall . Chism 's trial is scheduled for October 7 . Both sides are expected back in court for a pre-trial hearing on April 9 .
Philip Chism , now Tuesday , helped investigators locate Collen Ritzer 's body after her death in October 2013 . Judge ruled 16 that a taped police confession is now not admissible . Police coerced Chism - then 14 - to confess when he wanted to remain silent , defense attorneys said . Items seized from Chism after arrest , including Ritzer 's credit cards , a bloody box cutter and women 's underwear , are allowed to be used at trial . Chism has deined raping and murdering the 24-year-old teacher .