The family of a former Clarksville student accused of allegedly killing his Massachusetts math teacher earlier this week may have returned to Tennessee, police sources said. Philip Chism, 14, reportedly used a box cutter to kill 24-year-old teacher Colleen Ritzer in a bathroom at Danvers High School in Danvers, north of Boston.Students returned to class on Friday for the first time since Wednesday's devastating incident. Chism's family moved from Clarksville to Massachusetts earlier this year. His father worked in the military while his mother trained DCS workers and worked at Austin Peay State University. News 2 spoke with the teen's uncle, Terrance Chism Blaine, who said he was baffled when he first learned his nephew was charged in the killing. "You know, you never imagine something like this could happen. I thought it was a prank call when it first happened. [He was] such a good kid," he told News 2. Police have yet to release a motive on Ritzer's death. Chism is being held without bond.