Two months after Pradyuman Thakur was found with his throat slit at a school near Delhi, the CBI has detained a student of Class 11 at the same school for the murder that stunned the country. Sources in the CBI who have spoken to the student said that he killed the younger child because he was academically weak and believed the school would postpone exams as a result of the crime. CBI sources said they have recovered the weapon used to kill Pradyuman from the bathroom and that a bus conductor arrested earlier for the murder is no longer a suspect.