SALEM, Mass. — A Massachusetts judge has rejected a bid to unseal search warrant documents in the case of a 14-year-old boy charged with killing his high school math teacher.Philip Chism is charged in the Oct. 22 slaying of Colleen Ritzer, a 24-year-old teacher at Danvers High School.Several news organizations, including The Associated Press, asked a judge to make the documents available for public view.