DANVERS, Mass. (MyFoxBoston.com) -- Newly released court documents suggest a teen accused of murdering his 24-year-old math teacher may have recorded the killing on his cell phone.
Investigators applying for a search warrant for Philip Chism's phone alleged the 15-year-old may have recorded evidence related to Colleen Ritzer's death on his phone before smashing the device and throwing it away.
Officials claim Chism admitted to killing Ritzer and told them he destroyed both their phones so that he couldn't be tracked.
"I destroyed them so that you would be unable to locate or track me due to the GPS capabilities of the phone," Chism is quoted as saying in court documents.
Investigators said Chism's explanation for destroying his phone "seems doubtful," saying it is "widely understood" that GPS capabilities can be disabled without breaking the device.
The officer requesting the search warrant, Massachusetts State Trooper Steven Buccheri, writes that based on the weapons Chism is alleged to have brought to school, he has reason to believe the crime was planned. He adds that based on his training, he knows suspects can "conduct Internet searches regarding methods of killing for planning purposes."
"I similarly know that perpetrators sometimes memorialize their planning in text messages or notes," the officer adds. "Based on my particular training and experience I know that teenagers maintain such records on their electronic devices, particularly their smart phones."
The officer went on to state that Chism admitted to killing Ritzer, but not to raping her.
"Chism admitted murdering Colleen Ritzer. During the course of the interview Chism denied having committed a sexual assault or any sexual touching of Ritzer whatsoever," Buccheri wrote.
Chism was charged with an additional count of aggravated rape last week. Court documents suggest Chism's DNA matched DNA found on the slain math teacher's body.
Investigators said Chism denied having sexually assaulted Ritzer or touching her in sexual manner. He claimed that he struck Ritzer once and cut her twice.
The 15-year-old was indicted in November on murder, aggravated rape and armed robbery charges. He is accused of attacking Ritzer inside a Danvers High School bathroom with a box cutter, slitting her throat and stealing her credit cards, iPhone, and underwear on Oct. 22.
According to the documents released Monday, Chism was caught on surveillance video running from the woods where Ritzer's body was found. Investigators said there appeared to be blood on his bare feet and jeans.
"For the next hour Chism can be seen moving around the school, changing into soccer clothing, briefly returning to the second floor bathroom, traveling around the athletic areas of the school and eventually apparently discarding his clothing into the woods," reads the documents in support of a search warrant.
Chism is scheduled to be arraigned Thursday on the additional aggravated rape charge.